Veritas Storage Foundation 5.1 SP1 Advanced Features Administrator"s Guide (5900-1503, April 2011)

Note: As space-optimized instant snapshots only record information about changed
regions in the original volume, they cannot be moved to a different disk group.
They are therefore unsuitable for the off-host processing applications that are
described in this document.
The contents of full-sized instant snapshots must be fully synchronized with the
unchanged regions in the original volume before such snapshots can be moved
into a different disk group and deported from a host.
See the Veritas Volume Manager Administrator’s Guide.
Storage Checkpoints
A Storage Checkpoint is a persistent image of a file system at a given instance in
time. Storage Checkpoints use a copy-on-write technique to reduce I/O overhead
by identifying and maintaining only those file system blocks that have changed
since a previous Storage Checkpoint was taken. Storage Checkpoints have the
following important features:
■ Storage Checkpoints persist across system reboots and crashes.
■ A Storage Checkpoint can preserve not only file system metadata and the
directory hierarchy of the file system, but also user data as it existed when the
Storage Checkpoint was taken.
■ After creating a Storage Checkpoint of a mounted file system, you can continue
to create, remove, and update files on the file system without affecting the
image of the Storage Checkpoint.
■ Unlike file system snapshots, Storage Checkpoints are writable.
■ To minimize disk space usage, Storage Checkpoints use free space in the file
system.
Storage Checkpoints and the Storage Rollback feature of Veritas Storage
Foundation for Databases enable rapid recovery of databases from logical errors
such as database corruption, missing files and dropped table spaces. You can
mount successive Storage Checkpoints of a database to locate the error, and then
roll back the database to a Storage Checkpoint before the problem occurred.
See “About database recovery using Storage Checkpoints” on page 195.
Symantec NetBackup for Oracle Advanced BLI Agent uses Storage Checkpoints
to enhance the speed of backing up Oracle databases.
See the Symantec NetBackup for Oracle Advanced BLI Agent System Administrator’s
Guide.
137Understanding point-in-time copy methods
About point-in-time copy technology