Symantec logo

vxassist

NAME

vxassist - create, relayout, convert, mirror, backup, grow, shrink, delete, and move volumes

SYNOPSIS

vxassist [ options ] [ -b ] addlog volume [ attribute...]

vxassist [ options ] [ -b ] convert volume [ attribute...]

vxassist [ options ] [ -b ] growby volume lengthchange [ attribute...]

vxassist [ options ] [ -b ] growto volume newlength [ attribute...]

vxassist help { alloc | attrs | layout | mirror | options | showattrs | space | usage }

vxassist [ options ] [ -b ] make volume length [ attribute...]

vxassist [ options ] [ -b ] maxgrow volume [ attribute...]

vxassist [ options ] [ -b ] maxsize [ attribute...]

vxassist [ options ] [ -b ] mirror volume [ attribute...]

vxassist [ options ] [ -b ] move volume storage-spec... [ attribute...]

vxassist [ options ] [ -b ] relayout { volume| plex} [ attribute...]

vxassist [ options ] remove { volume | mirror | log } volume [storage-spec...] [ attribute...]

vxassist [ options ] shrinkby volume lengthchange [ attribute...]

vxassist [ options ] shrinkto volume newlength [ attribute...]

vxassist [ options ] snapabort volume

vxassist [ options ] snapback snapvolume

vxassist [ options ] snapclear volume [snap_object]

vxassist [ options ] snapprint [volume]

vxassist [ options ] snapshot volume [snapvolume] [ attribute...]

vxassist [ options ] [ -b ] snapstart [nmirror=number] volume [ attribute...]

vxassist [ options ] snapwait volume

DESCRIPTION

The vxassist utility is a command-line interface to the VERITAS Volume Manager (VxVM) that:

Specify the appropriate keyword to vxassist to select an action to perform.

Each operation can be applied to only one disk group at a time. For most keywords, the volume operand specifies the volume on which to operate. For the make operation, attributes that name specific disks can be used to determine a default disk group, according to the standard disk group selection rules described in vxintro(1M). A specific disk group can be specified with -g diskgroup. If this option is not specified, and an alternate default disk group is not defined by specifying the diskgroup attribute on the command line or in a defaults file (usually /etc/default/vxassist), the default disk group is determined using the rules given in the vxdg(1M) manual page.

Many vxassist operations can take a set of attributes that specify such things as how to lay out volumes, or on which sets of disks to build them. There are two basic types of attributes:

Storage specification attributes are either simple disk names (for example, disk01), or groups of disks selected by controller or target. For example, ctlr:c1 specifies all disks on the second SCSI controller.

You can exclude (negate) storage specification by specifying the exclamation character (!) prefix. (Note: You may also need to escape the ! character to prevent it being interpreted by the shell.)

Other attributes are of the form attrname=value; these additional attributes can specify the type of a volume (mirrored, RAID-5, striped, logged), layout policies (contiguous, spanning), mirroring requirements (mirror across controllers and SCSI targets), and constraint parameters (constrain allocations to a single controller). See the ATTRIBUTES section below for a complete list of attribute specifications.

If no non-excluded storage specification attributes are given, any non-reserved, non-volatile, non-spare, non-excluded disk can be used to allocate storage. Attributes may constrain the selection, particularly with respect to the selection of multiple disks. For example, the command:

vxassist make mirvol 500m layout=mirror,log mirror=ctlr \!ctlr:c1

requests that vxassist create a new mirrored volume on any disks that are not on the second SCSI controller. The mirror=ctlr attribute constrains the selection of disks so that the mirrors are created on different controllers.

KEYWORDS

addlog

Adds a log or DCO to a volume.

DCO is a data change object, used for Persistent FastResync. Note: This operation is only supported for version 0 DCOs.

DRL is a dirty region log, used for speedy recovery of mirrors after a system crash.

Sequential DRL is a form of DRL that is optimized for volumes that are written to sequentially, such as database log volumes.


  Note    For volumes with version 20 DCOs, DRL and sequential DRL are supported within the DCO volume itself. You can specify the dcoversion=20 attribute to the vxassist make command to create a volume with a version 20 DCO, or you can use the vxsnap prepare command to add a version 20 DCO to a volume. You cannot use the vxassist addlog command to add a version 20 DCO to a volume.


DCM is a data change map, used for fast resynchronization of a secondary RVG with its primary.

Mirrored volumes are associated with DRL or sequential DRL logs.

RAID-5 volumes are associated with RAID-5 logs.

Replicated volumes are associated with DCM logs.

By default, when adding a log, vxassist attempts to determine the correct type of log to add, even if no logtype attribute is specified. For example, if the volume is part of an RVG, vxassist attempts to create a DCM log.

When adding a DRL, RAID-5 or DCM log to a volume for the first time, the loglen attribute can be used to specify the length of the log; on adding additional logs, the loglen attribute is ignored and the existing log length is used. If a loglen which is too large or small to be practical is specified, vxassist may adjust the length to a reasonable size. If no loglen attribute is supplied, vxassist picks an appropriate log size. Other attributes can be specified to indicate desired properties for the new allocations. Mirroring constraints do not apply to logs, though storage constraints can be specified that limit the logs to disk sets already used by the volume.

Adding a version 0 DCO to a volume creates a DCO object that is associated with the volume, and a DCO volume that is associated with the DCO object. When created for a non-layered volume with at least 2 data plexes or for any layered volume, the default DCO volume has 2 DCO plexes (mirrors for redundancy), each of length 132 blocks. When created for a non-layered volume with a single data plex, the default DCO volume has a single unmirrored DCO plex of length 132 blocks.


  Note    The actual length may be rounded up to the disk group alignment value (see vxdg(1M)).



  Note    To allow operation of the dynamic disk group split/join feature (see vxdg(1M) for more information), vxassist attempts to place version 0 DCO plexes on the same disks as the plexes of the corresponding data volume. This allocation policy may not succeed if there is insufficient disk space. vxassist then uses available space in the remaining disks of the disk group. This may prevent certain disk group split or move operations if the DCO plexes cannot accompany their parent data volume. To overcome this, you can use storage specifications to specify explicitly the disks on which the DCO plexes are to be configured.



  Note    Adding a DCO does not enable Persistent FastResync on the parent volume unless fastresync=yes is also specified.


Adding a DRL log to a mirrored volume creates a single log subdisk and a new plex to contain that subdisk. The new plex is then attached to the volume. Note: For volumes with version 20 DCOs, DRL is supported within the DCO volume itself. Dedicated DRL log plexes should not be created for such volumes.

Adding a RAID-5 log to a RAID-5 volume involves creating a new plex that is attached to the volume as a log plex.

Adding a DCM log to a replicated volume adds two logs (by default), each consisting of a log plex and associated subdisk. DCM logging can co-exist with DCO.

convert

Converts a volume layout to a mirror-stripe from a stripe-mirror, or from a mirror-stripe to a stripe-mirror. Also converts to mirror-concat from a concat-mirror, or from a mirror-concat to a concat-mirror.

growby | growto

Increases the length of the named volume to the length specified by newlength (growto), or by the length specified by lengthchange (growby). Specify the new length, or change in length, in VERITAS Volume Manager standard lengths (see vxintro(1M)). The growto operation fails if the new length is not greater than the current volume length. The length of the volume is increased by extending existing subdisks in the volume, or by adding and associating new subdisks. Plexes that are not already fully populated (that is, sparse) are left unchanged. Log-only plexes are also left unchanged.


  Note    Following a relayout, specify the attribute layout=nodiskalign to the growby and growto commands if you want the subdisks to be grown using contiguous disk space.



  Note    When you grow a volume, it is recommended that you also grow any file system that is configured on that volume (see vxresize(1M)). vxassist does not resize file systems (or other uses of the volume, such as databases) that reside on the volume. If necessary, use the appropriate application command to adjust the layout of data in the volume after the grow operation has finished.


When a volume is grown, the volume may be converted from one layout to another as a side effect. For example, a volume that has the mirror-stripe layout may be converted to stripe-mirror when it is grown. This kind of conversion is done if vxassist determines that the new volume is too small or large for the original layout. If the new volume layout is inappropriate, use the convert operation between layered and non-layered forms. See Layout Specifications for a description of the methods used to determine disk layouts.


  Note    The relayout operation requires all mirrors in a volume to have the same layout. If a mirrored volume is composed of mixed plex layouts, relayout the mirror plexes to the same layout before attempting to relayout the volume.


You can specify attributes to indicate properties for the new allocations. Any mirroring constraints still apply between all extensions to the existing mirrors and the other mirrors. Growing of a volume requires that the volume be enabled.

When the size of a replicated volume changes, you can ensure that the size of the DCM is appropriate by removing all the DCM logs and adding them back without specifying the loglen attribute.

help

Displays information on vxassist usage and VERITAS Volume Manager attributes. For example, to display information about using vxassist attributes, enter:

vxassist help attributes

make

Creates a volume with the specified name and the specified length. The length is specified as a standard VERITAS Volume Manager length (see vxintro(1M)). You can specify attributes to indicate various properties and storage locations for the created volume. See Layout Specifications for a description of the methods used to determine disk layouts.

maxgrow

Reports the maximum size a volume can grow given its attributes and given the free storage available.

maxsize

Reports the maximum size a volume could be created with given the attributes specified and given the free storage available.

mirror

Creates a new mirror (or plex) and attaches it to the volume. This operation is allowed only if the volume is enabled. Attributes can be specified to indicate various desired properties and storage locations for the created volume. Attributes that constrain mirroring (such as requiring that mirrors be on separate groups of disks) apply between the existing mirrors of the volume and the new mirror.

move

Moves subdisks within the named volume off the excluded storage specified on the command line. Excluded storage is specified with a prefix of !. The move operation requires that at least one excluded storage specification be given.

If the volume is enabled, subdisks within detached or disabled plexes (or detached log or RAID-5 subdisks) are moved without recovery of data. If the volume is not enabled, stale log or RAID-5 subdisks, or subdisks within STALE or OFFLINE plexes, are moved without recovery; if there are other subdisks within a non-enabled volume that require moving, the move operation fails.

For enabled subdisks in enabled plexes within an enabled volume, the data within subdisks are moved to the new location, without loss of availability (or redundancy) of the volume.

relayout

Changes a volume layout or properties. This operation changes the number of columns in a stripe or the stripe width of a volume. It also converts a volume to or from RAID-5, concatenated-mirror, striped, striped-mirror or any similar layout.


  Note    The relayout operation internally generates unique data object names (for example, v2-Dp02) when it converts a volume to a specified destination layout.



  Note    Following a relayout, specify the attribute layout=nodiskalign to the growby and growto commands if you want the subdisks to be grown using contiguous disk space.


After relayout to a layered form, a volume may be converted to a non-layered form. For example, to convert from a 4-column mirror-stripe to a 5-column mirror-stripe, first relayout the volume as a stripe-mirror:

vxassist relayout vol1 nstripe=5

If you view the volume with vxprint during relayout, the volume shows several subvolumes that are used during the change, and a more complex configuration than usual.

After the new column is added, the volume is in stripe-mirror layout. Use vxassist convert to convert back to a mirror-stripe layout:

vxassist convert vol1 layout=mirror-stripe


  Note    If the system crashes during relayout or conversion, the process continues when the system is rebooted. However, if the crash occurred during the first stage of a two-stage relayout and convert operation, only the first stage is subsequently completed after rebooting. You must run vxassist convert manually to complete the second stage.


remove volume | mirror | log

Deletes the entire volume, one or more mirrors, or one or more logs, according to the argument. When deleting a mirror or a log, specify the storage to be removed using the attribute form !diskname (see Storage Specifications below). For example, to remove a mirror on disk01, enter:

vxassist remove mirror vol01 !disk01

See vxplex(1M) for an example of an alternative method of removing a mirror from a volume.

Use the logtype= attribute to specify the type of log to be removed. For example, specify logtype=drl to remove a DRL log.


  Note    Specifying logtype=dco completely removes a version 0 DCO object, DCO volume and any snap objects that are associated with the specified volume, and also disables FastResync on the volume. To remove a version 20 DCO and DCO volume, use the vxsnap unprepare command.


The alloc=, nmirror=, and nlog= attributes also determine the number of mirrors or logs remaining after the remove operation completes. When the number of mirrors drops to 1, logs are also removed.

By default, vxassist removes 1 mirror or 1 log.

shrinkby | shrinkto

Decreases the length of the named volume to the length specified by newlength (shrinkto), or by the length specified by lengthchange (shrinkby). Specify the new length, or change in length, in VERITAS Volume Manager standard lengths (see vxintro(1M)). The shrinkto operation fails if the new length is not less than the current volume length.

The length of a volume is decreased by removing and shortening subdisks to leave each plex with the requested volume length. The freed space can then be allocated for use by other volumes. Log-only plexes are left unchanged.

When a volume is shrunk, the volume may be converted from one layout to another as a side effect. For example, a volume that has the mirror-stripe layout may be converted to stripe-mirror when it is shrunk. This kind of conversion is done if vxassist determines that the new volume is too small or large for the original layout. If the new volume layout is inappropriate, use the convert operation between layered and non-layered forms. See Layout Specifications for a description of the methods used to determine disk layouts.


  Note    You cannot resize volumes comprised of different plex layouts. If you try to do so, an error message displays stating that the volume contains differing layouts.


Caution: Data can be lost or corrupted if file systems or other organized data residing on a volume are not shrunk before shrinking the volume. vxassist does not resize file systems (or other uses of the volume, such as databases) that reside on the volume. You can use the vxresize command to shrink file systems on the volume (see vxresize(1M)). Otherwise, use the appropriate application command to adjust the layout of data in the volume before initiating the shrink operation. You must specify the -f option to forcibly shrink volumes of usage type fsgen or raid5.

snapabort

Removes the mirror snapshot when a snapstart mirror has been started (and eventually completed).

snapback

By default, finds one plex in the snapshot volume that has the snap_rid field set, and attaches it to the original volume. If the plex is the last in a volume, that volume is removed from the disk group.


  Note    The snapshot volume and the original volume must be in the same disk group.


If the -o allplexes option is specified, all snapshot plexes in the same disk group are reattached. Alternatively, if the nmirror=number attribute is specified, only number plexes are reattached.

The direction of the resynchronization can be determined by specifying either resyncfromoriginal or resyncfromreplica as the useopt argument to the -o option. To choose the original volume as the preferred copy of the data, use -o resyncfromoriginal. To choose the replica as the preferred copy of the data, use -o resyncfromreplica.


  Note    Always unmount the snapshot volume (if mounted) before using snapback. You must also unmount the original volume (if mounted) before using the -o resyncfromreplica option.


snapclear

Clears the FastResync map, removes any snap objects, and clears the snap_rid field of the volume.


  Note    snapback cannot be invoked after snapclear is used.


If Persistent FastResync is enabled and the original volume and the snapshot volume are in different disk groups, snapclear removes the snap object and clears the FastResync map for the snapshot volume that corresponds to the snapshot object. To stop tracking on the original volume for the snapshot volume, specify the snap object, snap_object, in the original volume that refers to the snapshot volume. You must also run vxassist snapclear separately on the snapshot volume. For example, if myvol1 and SNAP-myvol1 are in separate disk groups mydg1 and mydg2 respectively, the following command stops tracking on myvol1 with respect to SNAP-myvol1:

vxassist -g mydg1 snapclear myvol1 SNAP-myvol1_snp

However, tracking is still enabled on SNAP-myvol1 with respect to myvol1. The following command turns this tracking off by specifying the snap object, myvol1_snp, in SNAP-myvol1 that points to myvol1:

vxassist -g mydg2 snapclear SNAP-myvol1 myvol1_snp

If Persistent FastResync is enabled and the original volume and the snapshot volume are in the same disk group, snapclear removes the snap records for both the original volume and the snapshot volume in addition to clearing their FastResync maps.


  Note    Either of the two previous examples stops Persistent FastResync tracking for both the snapshot volume (SNAP-myvol1) and the original volume (myvol1) if they are in the same disk group.


To support Non-Persistent FastResync and to be compatible with previous versions of VxVM, a single snapshot volume can be specified as the argument to snapclear, for example:

vxassist -g myolddg snapclear SNAP-myoldvol

snapprint

Displays the associations between the original volumes and their respective replicas. If a volume is specified, output is displayed only for that volume. An error message is displayed if FastResync is not enabled on the volume.

The following information is displayed:

V NAME USETYPE LENGTH

SS SNAPOBJ NAME LENGTH %DIRTY

DP NAME VOLUME LENGTH %DIRTY

v v1 fsgen 20480

ss SNAP-v1_snp SNAP-v1 20480 4

dp v1-01 v1 20480 0

dp v1-02 v1 20480 0

v SNAP-v1 fsgen 20480

ss v1_snp v1 20480 0

# vxassist -g mydg snapprint v2

V NAME USETYPE LENGTH

SS SNAPOBJ NAME LENGTH %DIRTY

DP NAME VOLUME LENGTH %DIRTY

v v2 fsgen 20480

ss -- SNAP-v2 20480 0

dp v2-01 v2 20480 0

v SNAP-v2 fsgen 20480

ss -- v2 20480 0

snapshot

Creates a new volume by taking one or more attached temporary mirrors (with state SNAPDONE) to use as its plexes. The nmirror=number attribute can be used to specify the number of mirrors in a snapshot volume. At least number SNAPDONE plexes must be available in the original volume. By default, one plex is used if nmirrors is not specified.

The comment attribute may also be used to set the comment field for the snapshot volume.

The following are examples of the use of the nmirror and comment attributes:

vxassist snapshot nmirror=2 \

comment="mirrored snapvol for myvol" myvol snapvol

Some usage types attempt to synchronize any in-memory data associated with the volume (such as unwritten file system modifications) when the snapshot operation is done. In particular, if the fsgen usage type is used with a volume containing a VERITAS File System (VxFS), then cooperating procedures ensure that all file system data is consistently flushed to the volume. For ext2 and other file system types, the synchronization operation calls sync. This makes the snapshot a better image, but it may leave some inconsistencies between in-memory file system data and the data residing on the backup image.

The snapshot command accepts more than one volume. All the given volumes are split atomically (in a single transaction). That is, all the given volumes are relatively consistent as a result of taking the snapshot. If you specify the -o allvols option without giving any volume names, vxassist attempts to create a sufficiently long vxplex command to take a snapshot of all the volumes in the disk group. You can use the -o name=pattern option to specify a name for the new volume. Otherwise, the default name assigned to the new volume has the form SNAP%d-%v.

snapstart

Creates a plex and attaches it to the named volume as a snapshot mirror. When the attach completes, the plex has state SNAPDONE and is a candidate for selection by the snapshot operation. Attributes can be specified to indicate the desired properties of the snapshot mirror.

The nmirror=number attribute can be used to specify the number of snapshot plexes to be attached to a volume. By default, number is 1.


  Note    For this command, the nmirror=number attribute is specified before the volume name.



  Note    To allow operation of the dynamic disk group split/join feature (see vxdg(1M) for more information), vxassist attempts to avoid placing snapshot plexes on the same disks as the plexes of the original volume or the plexes of its associated DCO volume. This allocation policy may not succeed if there is insufficient disk space. vxassist then uses any other available space in the disk group. This may prevent certain disk group split or move operations if the snapshot plexes and their associated DCO plexes cannot be physically separated from the plexes of the original volume or the plexes of its DCO volume. To overcome this, you can use storage specifications to specify explicitly the disks on which the snapshot plexes are to be configured.


snapwait

Waits for an attached mirror to become available on a volume if a snapstart mirror attach is done as a background task (such as using the -b option). The operation exits when the snapshot is complete. Available snapshot plexes are flagged with state SNAPDONE.

OPTIONS

-b

Performs extended operations in the background. This option applies to plex consistency recovery operations for make, growto and growby, to plex attach operations started by mirror and snapstart, to relayout operations started by relayout, and to the addlog, convert, maxgrow, maxsize, move and remove operations.

-d defaults

Specifies a file containing defaults for various attributes related to volume creation and space allocation. If not specified, this defaults to /etc/default/vxassist.

-f

Forces operations not usually allowed by vxassist.

-g diskgroup

Specifies the disk group for the operation, either by disk group ID or by disk group name. If this option is not specified, and an alternate default disk group is not defined by specifying the diskgroup attribute on the command line or in a defaults file (usually /etc/default/vxassist), the default disk group is determined using the rules given in the vxdg(1M) manual page.

-n

Prevents the system defaults file being read.

-o useopt

Passes in options specific to a usage type to the operation. A certain set of operations are expected to be implemented by all usage types:

allplexes

Specifies that all available snapshot plexes in a disk group are to be reattached to their original volume during a snapback operation.

allvols

Takes a snapshot of all the volumes in the disk group. An error results if one or more volumes do not have a plex that is usable for the snapshot.

iosize=size

Performs copy and recovery operations in regions with the length specified by size, which is a standard VERITAS Volume Manager length number (see vxintro(1M)). Specifying a larger number typically causes the operation to complete sooner, but with greater impact on other processes using the volume. The default I/O size is 1 megabyte.

name=pattern

Specifies the template for naming new snapshot volumes. The pattern consists of characters and one or more of the following specifiers:

%%

Single percent character.

%d

Unique serialization number expressed as a decimal integer.

%g

Disk group name.

%m

Mirror's original name.

%s

Serialization string expressed as a sequence of one or more lower case letters.

%S

Serialization string expressed as a sequence of one or more upper case letters.

%v

Volume name.

%x

Unique serialization number expressed as a lower-case hexadecimal integer.

%X

Unique serialization number expressed as an upper case hexadecimal integer.

The default template name for a new snapshot volume is SNAP%d-%v.

numchild=number

Specifies the number of child processes that are used to perform resynchronization during a snapback operation. The default value of number is 1 (no child processes), which is the same as specifying a number of 0. Specifying a larger value for number potentially speeds up resynchronization, although the effectiveness of this depends to some extent on the underlying characteristics of the disk array. No further benefit in performance may be noticeable for a value for number greater than 3.

By default, the child processes divide the volume into equally sized chunks, which they then resynchronize independently with the volume. This behavior may be modified using the useopt sequential.


  Note    A large iosize of 1m or 2m is recommended for use with this option.


ordered

Specifies that ordered allocation should be used to create a new volume. For more information, see the Ordered Allocation section below.

readonly

Specifies that a read-only replica volume is created during a snapshot.

renamesnapplex

Specifies that a snapshot plex is renamed when the snapshot operation is used to create a snapshot volume. If this option is not specified, the plex retains the same name that it had in the original volume.

resyncfromoriginal

Performs a resync using the data in the original volume during a snapback.

resyncfromreplica

Performs a resync using the data in the snap plex during a snapback.

sequential

When specified with the useopt numchild for values of number greater than 1, the child processes co-operate in resynchronizing regions of the volume that are close together, starting at the beginning of the volume and moving to the end. This creates more overhead for the resynchronization, but it potentially makes better use of the sequential read-ahead buffer of the physical disks.

slow[=iodelay]

Reduces the impact on system performance of copy operations. Copy and plex consistency recovery operations are usually a set of short operations on small regions of the volume (typically 1 megabyte). This option inserts a delay between the recovery of each such region. A specific delay can be specified with iodelay as a number of milliseconds, or a default is chosen (normally 250 milliseconds).

-p

Prints only the maximum size with no text wrappers (used with maxsize and maxgrow).

-r

Includes spare disks (reserved for hot-relocation) in the calculation.

-t tasktag

Marks any tasks that are registered to track the progress of an operation with the tag tasktag. This option is passed to utilities called by vxassist, so any child tasks are also tagged with tasktag. The tag specified by tasktag is a sequence of up to 16 alphanumeric characters.

-U usetype

Limits the operation to volumes that have this usage type. Any attempt to operate on volumes that have a different usage type fails.

For a make operation, this option specifies the usage type of the volume to be created. Otherwise, the default usage type set in the /etc/default/vxassist file is used, or if such an entry does not exist, the usage type is set to fsgen.

-v

Traces calls to other utilities to determine which VERITAS Volume Manager commands vxassist is executing.

Hardware-Specific Options

Some environments provide guidelines to optimize VxVM's interaction with intelligent storage systems. If these guidelines are present, VxVM follows the guidelines when creating volumes or allocating space for volumes. By default, vxassist only creates volumes that conform with these guidelines. The following options change the behavior of vxassist operations make, mirror, grow and shrink :

-o override

Performs the specified vxassist task for the specified volume and ignores any storage-specific guidelines. Overriding the guidelines is not recommended as it can result in incompatible objects, or objects that cannot be administered by VxVM and any associated software that exploit storage-specific features.

-o verify

Verifies that the vxassist task for the specified volume can be performed without violating any storage-specific guidelines, but does not commit or perform any task. If any guidelines are violated, vxassist exits with an error message.


  Note    These options need a separate license. Without the license, vxassist ignores the specified option.


Refer to the vendor-specific documentation for more information on how intelligent storage systems can interact with VxVM.

ATTRIBUTES

Attribute values for various purposes can be specified with arguments of the form attribute=value. Attributes can also be passed in through a defaults file. Default attribute values can be stored in the file /etc/default/vxassist.

Attributes are selected according to the order in which they are scanned. In general they are taken in decreasing priority of being specified on:

1.

The command line.

2.

The specified defaults file (as supplied with the -d command line argument).

3.

The system defaults file (as specified in /etc/default/vxassist).

Attributes from all sources have the same form. However, in some cases, command-line attributes change default behaviors in ways that attributes in the defaults file do not. In particular, references to mirroring (such as specifying a mirror count) or logging (such as specifying a log count or length) on the command line cause mirroring or logging to happen by default. If such attributes are specified in a defaults file, they indicate the attributes that would be used if mirroring or logging were enabled.

Attributes are either storage specifications (possibly negated), or are in the form attribute=value. In a defaults file, attributes are separated by a space or are on separate lines. Blank lines in a defaults file are ignored, and comments can be included with the standard # convention.

Storage Specifications

Storage specification attributes have one of the following forms:

[!]diskname

Specifies (or excludes) a disk. diskname refers to a disk media record name in a VERITAS Volume Manager disk group.

[!]diskclass:instance

Specifies (or excludes) a set of disks. diskclass names a particular type of disk grouping (for example, ctlr to indicate groups of disks on a single controller), and instance specifies which grouping of that type (for example c1). Each type of disk class has a particular format for specifying instances of the class.

diskclass:same

Specifies that the allocation must be constrained to include disks from the same instance of the given class. For example, a storage specification of diskparam:same indicates that all disks selected must have the same basic parameters (tracksize, cylinder size, size, and revolutions-per-minute), but does not specify which specific parameters to use.

The defined disk classes (and alternate names, or aliases, for those classes) are as follows:

ctlr (alias: c, ctrl, cntrl, controller)

Specifies disks from a particular host bus adapter (HBA) controller. For HBA drivers that support the SCSI_IOCTL_GET_BUS_NUMBER ioctl, VxVM designates the first controller as c0, the second controller as c1, and so on. For HBA drivers that do not support this ioctl, VxVM generates a controller number by adding 256 to the major number. For example, the identifier c259 would be assigned to an IDE controller driver which has a major number of 3.

da

Specifies a VERITAS Volume Manager disk (VM disk) by device name (disk access record name). For example, sdc indicates a VM disk defined on disk sdc.

device (alias: d)

Specifies all VM disks on a physical disk. The physical disk is specified in the form sdb, which equates to the whole system disk. Typically, only one VM disk device is created for each physical disk.

dm (alias: disk)

Specifies a VM disk by disk name (disk media record name) in the disk group of the volume. Specifying a disk class type of dm or disk is equivalent to giving a storage specification with no disk class name.

Other Attributes

Other attributes are of the form attribute=value. The attribute name in an attribute value pair never contains a colon, so it is possible to specify a disk that has an equal sign in its name using the storage specification dm:disk01=a. Without the dm: prefix, disk01=a would cause an error indicating an unrecognized attribute.

Defined attributes (and common aliases) are:

alloc=storage-spec[,storage-spec,...]

Specifies a VM disk by disk name (disk media record name) in the disk group of the volume. Specifying a disk class type of dm or disk is equivalent to giving a storage specification with no disk class name.

Specifies storage as single attributes. This is useful in a defaults file, so that all attributes (including storage specifications) are in the attribute=value format. Any number of storage specifications can be specified, separated by commas. More than one alloc attribute can be specified, in which case they are logically concatenated to form one longer list.

col_switch=size1,size2[,...]

When creating a volume using ordered allocation (-o ordered), specifies how much space to allocate from each listed disk to a concatenated column before switching to the next disk. The number of size arguments (switch points) determines how many disks are concatenated to form a column. size1 space is allocated from the first disk, size2 space is then allocated from the second disk, and so on. The switch points are applied identically to all columns in the volume being created.

For more information, see the Ordered Allocation section below.

comment=comment

Specifies a comment to give to a volume when it is created. This comment can be displayed with vxprint -l, and can be changed, at a later time, with vxedit set. This attribute can be used with the make and snapshot operations.

dcolen=number (alias: dcologlen)

Specifies the length of each plex in a version 0 DCO volume. By default, specifying a length on the command line creates a DCO volume. The default length is 132 blocks, and any specified value should be an integral multiple of 33 blocks between 33 and 2112 blocks.


  Note    The actual length may be rounded up to the value of the disk group alignment (see vxdg(1M)).


dcoversion=0|20

Specifies the type of DCO and DCO volume to be created for a volume when using the make command. A version 0 DCO supports Persistent FastResync. A version 20 DCO supports Persistent FastResync, instant snapshots, and DRL and sequential DRL logs within the DCO volume. If not specified, the default DCO version is 0.

Creating a version 20 DCO associates a DCO object with a volume, and associates a DCO volume with the DCO object. When created for a non-layered volume with at least 2 data plexes or for any layered volume, the default DCO volume has 2 DCO plexes (mirrors for redundancy) with a default region size of 64KB. A different region size can be specified by using the regionsz attribute.

diskgroup=disk-group (alias: dg)

Specifies the type of DCO and DCO volume to be created for a volume when using the make command. A version 0 DCO supports Persistent FastResync. A version 20 DCO supports Persistent FastResync, instant snapshots, and DRL and sequential DRL logs within the DCO volume. If not specified, the default DCO version is 0.

Specifies the disk group for an operation. If a disk group is specified in a defaults file, then it just specifies the default disk group to use for the make operation, if no other means of determining the disk group can be used. If specified as a command line attribute, it has the same effect as specifying a disk group with the -g option (the operation is forced to apply to the given disk group).

excl=yes|y|on|true|no|n|off|false

Sets or clears the EXCLUSIVE flag on the volume. A volume in exclusive open state can be opened by only one node in the cluster at a time. Multiple opens of an exclusive volume from the same node are permitted. Non-exclusive volumes can be simultaneously opened by more than one node. After a node opens an exclusive volume, every other node's open attempt fails until the last close of the volume by the first opener. Such an open failure returns a EBUSY error code.


  Note    Only available if the VERITAS Volume Manager cluster feature is enabled.


fastresync=yes|y|on|true|no|n|off|false (alias: fmr)

Enables or disables both Persistent and Non_Persistent FastResync. If enabled, FastResync is non-persistent if a DCO object and a DCO volume are not associated with a volume, and it is persistent if a DCO object and DCO volume are associated with a volume.


  Note    A license is necessary to use the FastResync feature.


fstype=file-system-type

Specifies the file system type for a new volume (this is used only with the make operation). The file system type parameter is used with the VERITAS Volume Manager vxresize utility, as well as with volume snapshots, copies, and dissociates (to select features that are used with VERITAS File System (VxFS)).

The file system type can be changed at any later time with the vxedit set operation.

group=owning-group

Sets the group ID for a new volume. The group ID can be specified numerically or with a system group name. This attribute is used only with the make operation. By default, volumes are created with group 0.

init=initialization-type

Specifies how to initialize a new volume. The default method (which can be selected explicitly with init=default) is to call vxvol start to perform a default initialization that is specific to a usage type. A new volume can be left uninitialized with init=none. The most useful non-default initialization that can be specified is init=zero, to clear the volume before enabling it for general use.

layout=layout-spec[,layout-spec,...]

Specifies a plex layout type (RAID-5, mirrored, unmirrored, striped, cylinder alignment), and turn some features on and off (such as logging). The list of layout specifications is given in the Layout Specifications section. By default, unmirrored, non-striped volumes are created without a log.

logdisk=disk[,disk,...]

When creating volumes using ordered allocation (-o ordered), specifies on which disks logs should be created. This attribute must be specified for RAID-5 volumes unless nolog or noraid5log is specified. For other types of volume layout, this attribute is optional, and if not specified any required logs are co-located with the data.

For more information, see the Ordered Allocation section below.

loglen=length

Specifies a log length to use for dirty-region log (DRL) subdisks for mirrored volumes, for RAID-5 log plexes, or for DCM log plexes for replicated volumes. By default, specifying a log length on the command line creates a log. Associating a log with a mirrored or RAID-5 volume is sufficient to enable its use.

A DCM log must be enabled using the vxrlink command. This is because it is used for failure recovery and synchronization of replicated volumes.

logtype=type

Specifies the type of log to use with a mirrored or replicated volume:

dcm

Select DCM (data change map). This is the default log type for replicated volumes.

dco

Select DCO (data change object). (This is used to implement Persistent FastResync, which is enabled by additionally specifying fastresync=on.) This creates a DCO object and a DCO volume with a plex size specified by the dcologlen attribute, and number of plexes specified using the ndcomirror attribute. The default names for the DCO object and DCO volume are vol_dco and vol_dcl respectively for a volume, vol.

If additional logging is required, it can be added to a volume by using the vxassist addlog command. DCO can co-exist with DCM logging for replicated volumes, or with DRL logging for mirrored volumes.


  Note    Additional version 20 DCO maps can be added by using the vxsnap addmap command.


drl

Select DRL (dirty region logging). This is the default log type for mirrored volumes.


  Note    For volumes with version 20 DCOs, DRL is supported within the DCO volume itself.


drlseq

Select sequential dirty region logging. This is identical to drl except that the number of dirty bits that can be set in the DRL is limited to the value of the tunable voldrl_max_seq_dirty (default value is 3). This is useful on volumes that are usually written to sequentially, such as database log volumes. Limiting the number of dirty regions allows for faster recovery if a crash occurs. However, if applied to volumes that are written to randomly, this type of logging can be a performance bottleneck as it limits the number of parallel writes that can be carried out.


  Note    For volumes with version 20 DCOs, sequential DRL is supported within the DCO volume itself.


none

Do not create a log.

region

Select dirty region logging; identical to drl.

RAID-5 logging is automatically selected when a log plex is added to a RAID-5 volume; it has no specific logtype.

If logtype is not specified for a volume, vxassist attempts to create the optimal type of log.

logmap_len=size

Specifies the maximum usable size in bytes of a DRL log to the addlog or make operations. This value is not constrained by any disk group alignment value.

max_nraid5column=number

(alias: maxraid5columns, max_nraidcolumn, max_nraid5stripe, max_nraidstripe, maxraidcolumns, maxraid5stripes, maxraidstripes)

Specifies the default maximum number of stripe columns for a RAID-5 volume (default value is 8). The rules for selecting the default number of RAID-5 stripe columns are described in the nstripe attribute.

max_ncolumn=number (alias: maxcolumns, max_nstripe, maxstripes)

Specifies the default maximum number of stripe columns, either for a RAID-5 volume (if max_nraid5stripe is not also specified) or for a striped plex (default value is 8). The rules for selecting the default number of stripe columns is described in the nstripe attribute.

max_regionloglen=length (alias: maxregionloglen)

Specifies the maximum default dirty region logging log subdisk length. If the user does not specify the dirty region log length for a volume, when creating the first log for a mirrored volume, vxassist uses a simple formula based on the log length. The default length is not be bounded by max_regionloglen (default value is 32k (32 kilobytes)).

min_ncolumn=number (alias: mincolumns, min_nstripe, minstripes)

Specifies the default minimum number of stripe columns for either a RAID-5 volume (if min_nraid5stripe is not also specified) or for a striped plex (default value is 2). The policy for selecting a default number of stripe columns is not allowed to select fewer than this number of columns.

min_nraid5column=number

(alias: minraid5columns min_nraidcolumn, min_nraid5stripe, min_nraidstripe, minraidcolumns, minraid5stripes, minraidstripes)

Specifies the default minimum number of stripe columns for a RAID-5 volume (default value is 3). The policy for selecting a default number of RAID-5 stripe columns is not allowed to create a RAID-5 volume with fewer than min_nraid5stripe stripe columns.


  Note    It is notionally possible to create a RAID-5 volume with 2 columns in VxVM. This is effectively a 2-way mirror with reads directed to alternate stripe units on the two columns. This can improve read performance over that of a unstriped 2-way mirror. However, such a layout is usually much more inefficient in CPU usage when writing to the volume and is not generally recommended.


mirror=[+|-]number|yes|no|diskclass[,...]

Specifies various mirroring parameters. Multiple mirroring parameters can be given, each separated by a comma. A decimal number indicates a specific number of mirrors to create, when creating a mirrored volume (equivalent to nmirror=number). yes indicates that volumes should be mirrored by default (equivalent to layout=mirror). no indicates that volumes should be unmirrored by default (equivalent to layout=nomirror).

Any other mirroring parameters specify that volumes should be mirrored across instances of a particular disk class (such as enclr, ctlr or target). For example, mirror=ctlr specifies that disks in a mirror should not be on the same controller as disks in other mirrors within the same volume. Similarly, mirror=enclr specifies that disks in a mirror should not be from the same enclosure as disks in other mirrors within the same volume.

Each mirror can contain disks from any number of instances of the disk class, but different mirrors cannot use disks from the same instance of the disk class.

mirrorconfine=diskclass[,diskclass,...]

Specifies a required list of disk classes for mirror confinement constraints. If this attribute is specified, a single mirror is confined to (that is, allocated from) a group of disks belonging to a specific disk class. Multiple mirrors can be allocated from a single disk class. Multiple disk classes cannot be used to allocate a mirror.

mode=permissions

Specifies the permissions for the block and character device nodes created for a new volume. The mode can be specified either as an octal number or symbolically. A symbolic mode is specified using the syntax given in chmod(1). This attribute is used only with the make operation. The default mode for a volume gives read and write access only to the owner.

ndcmlog=number (alias: ndcmlogs, ndcms, ndcm)

Specifies the number of DCM log plexes to create. The default number is 2 which creates a mirrored DCM log.

ndcomirror=number (alias: ndco, ndcos, ndcolog, ndcologs, ndcomirrors)

Specifies the number of DCO plexes to create for a DCO volume. A value for number of 2 or greater creates a mirrored DCO volume. For non-layered volumes, the default number is set to the lesser of the number of data plexes in the parent volume or 2. For layered volumes, the default number is set to 2.

nlog=[+|-]number, (alias: nlogs, logs)

Specifies the number of logs to create, by default, for a RAID-5, mirrored, or replicated volume (assuming that logs are to be created). The number of logs to create can be specified independently for RAID-5 or mirrored volumes using the nraid5log and nregionlog attributes. For a relayout, this value can be preceded by a + or a - to add or subtract logs.

nmirror=[+|-]number, (alias: nmirrors, mirrors)

Specifies the number of mirrors to create when mirroring a volume (default value is 2).

For a relayout, this value can be preceded by a + or a - to add or subtract mirrors. The value can also be specified as src_nmirror to preserve the number of mirrors.

This attribute is also used to specify the number of snapshot plexes to be attached to a volume by a snapstart operation, and the number of plexes in a snapshot volume for snapshot and snapback operations. For a snapshot, there must be number SNAPDONE plexes available in the original volume. For a snapback, there must be number snapshot plexes available in the snapshot volume (which must also be in the same disk group as the original volume).

nraid5log=number

(alias: nraid5logs, raid5logs, nraidlog, nraidlogs, raidlogs)

Specifies the number of log plexes to create for a new RAID-5 volume (default value is 1). This attribute is used only with the make operation.

nraid5stripe=[+|-]number

(alias: raid5stripes, nraid5column, nraidstripe, raidstripes, raidcolumns, nraidcolumn, raid5columns)

Specifies the number of stripe columns to use when creating a new RAID-5 volume (the default is to adjust the number to available disks). This attribute is used only with make and relayout operations. For the relayout operation, the default is the same number of stripe columns the volume has. For a relayout, this value can be preceded by a + or a - to add or subtract columns.

nregionlog=number (alias: nregionlogs, regionlogs, ndrl)

Specifies the number of log subdisks to create for a new mirrored volume (default value 1). This attribute is used only with the make operation, and only if logging is requested for the volume.

nstripe=[+|-]number

(alias: stripes, ncolumn, ncolumns, ncol, ncols, columns, cols)

Specifies the number of stripe columns to use when creating a new RAID-5 volume (with the make operation) or when creating a striped plex (with the make, relayout, mirror, and snapstart operations). The usual default behavior is to adjust to the number of available disks, but there are exceptions to this rule.

When creating an unmirrored striped volume, the default behavior is to adjust to half the number of available disks. This allows for the subsequent addition of a mirror to the volume. (A volume that does not have data redundancy cannot recover from disk failure.)

For relayout operations, the default behavior is to conserve the number of stripe columns in the volume. In such operations, the value of number can be preceded by + or - to specify a number of columns that are to be added or subtracted.

probe_granularity=size

Specifies the granularity for the maxsize request. The default size value is 1 megabyte.

raid5_stripeunit=width

(alias: raid5_stwid, raid5_st_width, raid5_stwidth, raid_st_width, raid_stripeunitsize, raid5_stripeunitsize, raid5_stripeunitwidth, raid_stwid, raid_stwidth, raid_stripeunit, raid_stripeunitwidth)

Specifies the stripe unit size to use when creating a new RAID-5 volume (default value is 16k (16 kilobytes)). This attribute is used only with the make operation.

raid5loglen=length (alias: raidloglen)

Specifies the log length to use when adding the first log to a RAID-5 volume. The default is four times the full stripe width (the stripe unit size times the number of stripe columns).

regionloglen=length (alias: drlloglen, drllen)

Specifies the log subdisk length to use when adding the first log subdisk to a mirrored volume. The default is chosen based on a formula involving the volume length.

regionsz=size

Specifies the size of each region that is tracked by a bit in the maps within a version 20 DCO volume. The value of size must be a power of 2 and be greater than or equal to 16k (16KB). The default value is 64k (64KB). The region size must also be no greater than half the value of the voliomem_maxpool_sz tunable. Otherwise, only a limited set of instant snapshot operations are permitted on the volume. For more information, see the vxsnap(1M) manual page.


  Note    The region size can only be specified for version 20 DCOs. It cannot be specified for version 0 DCOs.


spare=no|only|yes

Controls the use of spare disks when hot-relocation is performed.

If set to yes, spare disks are used. If necessary, free space is also used on disks that have been marked nohotuse=off. This is the default behavior.

If set to only, relocation storage is allocated using only spare disks.

If set to no, spare disks are not used. Alternatively, do not mark any of your disks as spares and do not mark them as available for use by hot relocation.

stripe=diskclass[,...]

Specifies that volumes should be striped across instances of a particular disk class. Each column can contain disks from any number of instances of the disk class, but different columns cannot use disks from the same instance of the disk class.

stripe-mirror-col-trigger-pt=size

Specifies a size that triggers the creation of a stripe-mirror volume. If the size of the volume is greater than the size specified in this attribute, then a stripe-mirror volume is created.

stripe-mirror-col-split-trigger-pt=size

Specifies a size that triggers the creation of a stripe-mirror-sd volume. If the size of each column is greater than the size specified in this attribute, then a stripe-mirror-sd volume is created.

stripe_stripeunit=width

(alias: stripe_stwid, stripe_stwidth, stripe_st_width, stripe_stripeunitsize, stripe_stripeunitwidth)

Specifies the stripe unit size to use when creating striped plexes to attach to a volume. When attaching a new plex, the default is to use the same stripe unit size as any other striped plexes in the volume. If the volume does not already contain striped plexes, the default value is 64k (64 kilobytes).

stripeunit=width

(alias: stwid, stripewidth, stwidth, st_width, stripe_width, stripeunitsize, stripeunitwidth)

Specifies the stripe unit size to use for either a RAID-5 volume or for striped plexes. stripeunit can be used to set the values for both raid5_stripeunit and stripe_stripeunit.

tmpsize=size

Specifies the size of the temporary storage used to perform a relayout operation.

tmpalloc=storage-spec[,storage-spec,...]

Specifies a set of storage specifications for the temporary storage required during a relayout operation. The format is the same as for the alloc attribute (a comma-separated list of storage specifications).

user=owning-user

Specifies the user ID for a new volume (default value is root). The user ID can be specified numerically or it can be a system login name. This attribute is used only with the make operation.

usetype=volume-usage-type

Specifies the usage type to use when creating a new volume (default value is raid5 for RAID-5 volumes; otherwise fsgens the default). This attribute is only used with the make operation. The usage type can also be specified using the -U option.

wantalloc=storage-spec[,storage-spec,...]

Specifies a set of desired storage specifications. This is useful in a defaults file to indicate desired storage specifications that should be discarded if they fail to yield a reasonable set of allocations. The format is the same as for the alloc attribute (a comma-separated list of storage specifications).

For example, a defaults file can name a specific controller type to use for allocations, if possible. When all disks on that type of controller are full, other controllers are used.

wantmirror=diskclass[,diskclass,...]

Specifies a desired list of disk class mirroring specifications. This is useful in a defaults file to indicate a set of desired mirroring constraints that can be dropped if they fail to yield a reasonable set of allocations.

For example, a defaults file can specify that volumes should be mirrored between disks on different controllers in the system. The constraint is dropped if the set of volumes builds up in such a way that a new volume cannot be mirrored across controllers.

wantmirrorconfine=diskclass[,diskclass,...]

Specifies a list of disk classes for mirror confinement constraints. A single mirror is confined to (that is, allocated entirely from) a group of disks belonging to a single disk class.

This is useful in a defaults file to indicate a set of mirror confinement constraints that can be dropped if they fail to yield a reasonable set of allocations. For example, a defaults file can specify that a single mirror be confined to disks of the same vendor:

wantmirrorconfine=vendor

If vxassist cannot allocate a mirror from disk devices of one vendor, this constraint is dropped and the mirror is allocated from disk devices of other vendors.

wantstripe=diskclass[,diskclass,...]

Specifies a desired list of disk class stripping specifications. This is useful in a defaults file to indicate a set of desired stripping constraints that can be dropped if they fail to yield a reasonable set of allocations.

For example, a defaults file can specify that volumes should be striped between disks on different controllers in the system. The constraint is dropped if the set of volumes builds up in such a way that a new volume cannot be striped across controllers.

Layout Specifications

The layout attribute specifies a comma-separated list of simple parameters (with no arguments) that apply to vxassist operations.

Two new layouts were added in the 3.0 release of VxVM: stripe-mirror and concat-mirror. In previous releases, whenever mirroring was used, the mirroring had to happen above striping or concatenation. Now there can be mirroring both above and below striping and concatenation.

Putting mirroring below striping mirrors each column of the stripe. If the stripe is large enough to have multiple subdisks per column, each subdisk can be individually mirrored. A similar concatenated volume would also mirror each subdisk individually. These new layouts enhance redundancy and reduce recovery time in case of an error. In a mirror-stripe layout, if a disk fails, the entire plex is detached, thereby losing redundancy on the entire volume. When the disk is replaced, the entire plex must be brought up to date. Recovering the entire plex can take a substantial amount of time. If a disk fails in a stripe-mirror layout, only the failing subdisk must be detached, and only that portion of the volume loses redundancy. When the disk is replaced, only a portion of the volume needs to be recovered.

The new volume layouts are more complex than the older volume layouts. Because the advantages of recovery time and improved redundancy are more important for larger volumes, it is best to continue using mirror-stripe and mirror-concat for most volumes and only use stripe-mirror and concat-mirror for very large volumes.

You can specify layout=mirror-stripe or layout=stripe-mirror to implement the desired layout. If you specify layout=stripe,mirror or layout=mirror,stripe, vxassist automatically determines the best layout for the volume. Unless there is a reason to implement a particular layout, it is best to let vxassist create the layout for each volume. Because the advantages of the new layouts are related to the size of the volume, vxassist creates the simplest configuration for smaller volumes and the more complex stripe-mirror for larger volumes.

The attributes stripe-mirror-col-trigger-pt and stripe-mirror-col-split-trigger-pt control the selection. They can be set in /etc/default/vxassist. Volumes that are smaller than stripe-mirror-col-trigger-pt are created as mirror-stripe, and volumes that are larger are created as stripe-mirror. If vxassist creates the stripe-mirror and the columns are larger than stripe-mirror-col-split-trigger-pt, the individual subdisks are mirrored instead of mirroring the columns of the stripe. By default, both of these attributes are set to one gigabyte.

The disk group must be created on a 3.0 or later release to use the new layouts, but older disk groups can be updated. See the vxdg upgrade command for more information on upgrading disk groups.

Defined layout specifications are:

concat-mirror

Specifies that new volumes should be concatenated and mirrored. The mirroring is handled at each subdisk level. The attribute stripe-mirror-col-split-trigger-pt is applied.

contig, nocontig

Disallows or allows (default) plexes, regular stripe columns, or RAID-5 stripe columns from using multiple regions of disk. If contig is specified, then plexes and columns must be allocated from a single contiguous region of disk. If this is not possible, the allocation fails. By default, vxassist tries to allocate space contiguously, but it can use multiple regions or multiple disks if required.

dgalign_checking={round|strict}

Controls how vxassist handles attributes that are subject to disk group alignment restrictions. If set to strict, the volume length and values of attributes must be integer multiples of the disk group alignment value. If set to round (default), attribute values are rounded up as required.

diskalign, nodiskalign

Aligns or does not align (default) subdisks on cylinder boundaries. When alignment is not disabled, subdisks are created beginning on cylinder boundaries and are extended to match the end of a cylinder. Dirty region log subdisks, however, are not cylinder aligned (they are usually only 2 or 3 blocks long). Instead, when creating log subdisks, spaces are located from the available disks that could not be turned into regular subdisks because the spaces are not cylinder aligned. For example, once one cylinder is used for a log subdisk, that cylinder cannot be used to create an aligned data (or RAID-5 log) subdisk, so other log subdisks are created there until that cylinder fills up.


  Note    vxassist always uses the disk group alignment value for EFI disks. If the value of the disk group alignment is greater than 1, specifying diskalign for EFI disks results in an error. The disk and cylinder alignment values for EFI disks are always set to 1. See vxdg(1M) for more information.


The diskalign attribute is not supported for layered volumes (concat-mirror and stripe-mirror).

grow, nogrow

Allows a volume to grow during a relayout operation.

log, nolog

Creates (or does not create) dirty region logs (for mirrored volumes) or log plexes (for RAID-5 volumes) when creating a new volume. This attribute can be specified independently for mirrored and RAID-5 volumes with the raid5log and regionlog layout specifications. The current implementation does not support the creation of DCM logs in the layout specification.

mirror, nomirror

Specifies that new volumes should be mirrored or unmirrored (default) respectively. For mirror, the attribute stripe-mirror-col-split-trigger-pt is applied, and the attribute stripe-mirror-col-trigger-pt is ignored.

mirror-concat

Specifies that new volumes should be mirrored. The mirroring is done at the volume level. The attributes stripe-mirror-col-trigger-pt and stripe-mirror-col-split-trigger-pt are ignored with this layout.

mirror-stripe

Specifies that new volumes should be mirrored and striped. The mirroring is done at the volume level. The attributes stripe-mirror-col-trigger-pt and stripe-mirror-col-split-trigger-pt are ignored with this layout.

raid5

Specifies that new volumes should be RAID-5.

raid5log, noraid5log

Creates (default) or does not create log plexes for RAID-5 volumes.

regionlog, noregionlog

Creates or does not create (default) dirty-region log subdisks for mirrored volumes.

shrink, noshrink

Allows or disallows shrinking of a volume during a relayout operation.

span, nospan

Allows (default) or disallows plexes, regular stripe columns, or RAID-5 stripe columns from spanning multiple disks. If nospan is indicated, then plexes or columns can be formed from multiple regions of the same disk, but cannot be formed from more than one disk.

stripe, nostripe

Specifies that new plexes should be striped or unstriped, respectively. When creating a new volume, the default is nostripe. When adding a new plex to an existing volume, the default is stripe if the volume already has one or more striped plexes, and nostripe in other cases. For stripe (when combined with mirror, the attributes stripe-mirror-col-trigger-pt and stripe-mirror-col-split-trigger-pt are applied.

stripe-mirror

Specifies that new volumes should be striped and mirrored. The mirroring is handled at each column level or subdisk level depending on the attribute stripe-mirror-col-split-trigger-pt.

stripe-mirror-col

Specifies that new volumes should be striped and mirrored. The mirroring is handled at each column level. The attributes stripe-mirror-col-trigger-pt and stripe-mirror-col-split-trigger-pt are ignored with this layout.

stripe-mirror-sd

Specifies that new volumes should be striped and mirrored. The mirroring is handled at each subdisk level.

Ordered Allocation

If the -o ordered option is specified when creating a volume, vxassist uses the specified storage in the following order:

1.

Concatenate disks.

2.

Form columns.

3.

Form mirrors.

For example, the following command creates a mirrored-stripe volume with 3 columns and 2 mirrors on 6 disks:

vxassist -o ordered make mirstrvol 10g layout=mirror-stripe \

nstripe=3 disk01 disk02 disk03 disk04 disk05 disk06

This command places columns 1, 2 and 3 of the first mirror on disk01, disk02 and disk03 respectively, and columns 1, 2 and 3 of the second mirror on disk04, disk05 and disk06 respectively.

For layered volumes, the same rules are used to allocate storage as for non-layered volumes. For example, the following command creates a striped-mirror volume with 2 mirrored columns:

vxassist -o ordered make strmirvol 10g layout=stripe-mirror \

nstripe=2 disk01 disk02 disk03 disk04

This command mirrors column 1 across disk01 and disk03, and column 2 across disk02 and disk04.

The col_switch attribute can additionally be used to specify how space on the disks is to be concatenated into columns. For example, the following command creates a mirrored-stripe volume with 2 columns:

vxassist -o ordered make strmir2vol 10g layout=mirror-stripe \

nstripe=2 col_switch=3g,2g disk01 disk02 disk03 disk04 \

disk05 disk06 disk07 disk08

This command allocates 3 gigabytes from disk01 and 2 gigabytes from disk02 to column 1, and 3 gigabytes from disk03 and 2 gigabytes from disk04 to column 2. The mirrors of these columns are then similarly formed from disks disk05 through disk08.

FILES

/etc/default/vxassist

System default settings file for vxassist attributes.

EXIT CODES

The vxassist utility exits with a non-zero status if the attempted operation fails. A non-zero exit code is not a complete indicator of the problems encountered, but rather denotes the first condition that prevented further execution of the utility.

See vxintro(1M) for a list of standard exit codes.

SEE ALSO

chmod(1), sync(1M), vxedit(1M), vxintro(1M), vxmake(1M), vxmend(1M), vxplex(1M), vxrelayout(1M), vxresize(1M), vxsd(1M), vxsnap(1M), vxtask(1M), vxvol(1M)