About using Veritas NetBackup to backup and restore Quick I/O files

Veritas NetBackup does not follow symbolic links when backing up files. Typical backup management applications are designed this way to avoid backing up the same data twice. This would happen if both the link and the file it points to were included in the list of files to be backed up.

A Quick I/O file consists of two components: a hidden file with the space allocated for it, and a link that points to the Quick I/O interface of the hidden file. Because NetBackup does not follow symbolic links, you must specify both the Quick I/O link and its hidden file in the list of files to be backed up.

To view all files and their attributes in the db01 directory:

	$ ls -la /db01
	total 2192
	drwxr-xr-x				2 root			root		96		Oct 20 17:39					.
	drwxr-xr-x				9 root			root		8192		Oct 20 17:39					..
	-rw-r--r--				1 db2			dba		1048576			Oct 20 17:39				.dbfile
	lrwxrwxrwx				1 db2			dba		22		Oct 20 17:39				dbfile ->\

In the example above, you must include both the symbolic link dbfile and the hidden file .dbfile in the file list of the backup class.

If you want to back up all Quick I/O files in a directory, you can simplify the process by just specifying the directory to be backed up. In this case, both components of each Quick I/O file will be properly backed up. In general, you should specify directories to be backed up unless you only want to back up some, but not all files, in those directories.

Because NetBackup is tightly integrated with the Veritas Database Edition for DB2, NetBackup backs up extent attributes of a Quick I/O file and restores them accordingly. Quick I/O files can then be backed up and restored as regular files using NetBackup, while preserving the Quick I/O file's extent reservation. Without this feature, restoring the file could cause the loss of contiguous reservation, which can degrade performance.

When restoring a Quick I/O file, if both the symbolic link and the hidden file already exist, NetBackup will restore both components from the backup image. If either one of or both of the two components are missing, NetBackup creates or overwrites as needed.