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About attributes

A storage attribute allows the properties of a LUN to be defined in an arbitrary conceptual space.

For example, attributes can describe the following properties:

• Disk access name
• Disk media name
• Manufacturer
• Model type
• Physical location, such as rack number, frame number, floor, building, or site
• Hardware RAID configuration
• Failover properties
• Performance properties

You can use disk tags to create storage attributes in addition to those that are intrinsically associated with the disk hardware, and which are automatically discovered or assigned by VxVM. Disk tags are administered by using the vxdisk command or the VEA graphical user interface.

For example, the following vxdisk settag command can be used to assign tags and optional values to each disk:

# vxdisk -g mydg settag Room=room1 mydg01 mydg02 mydg03 mydg04

# vxdisk -g mydg settag Room=room2 mydg05 mydg06 mydg07 mydg08

This sets the attribute tag Room on the disks (mydg01 through mydg08) with values that represent the physical location (room1 or room2).

Attributes may be used to capture information about the following special features of storage:

• Hardware-supported cloning, such as EMC Business Continuity Volumes (BCV)
• Hardware-supported replication, such as the EMC Symmetrix Remote Data Facility (SRDF)
• Hardware redundancy, such as mirrored parity, and caching

It should only be necessary to enter such information manually if VxVM cannot discover it automatically. An example of a user-defined attribute is physical location.

Attribute names and their string values are case sensitive. You can use the vxdisk listtag command or the VEA graphical user interface to discover the correct spelling of LUN attribute names.