Veritas™ File System 5.0.1 Administrator's Guide
See “How a Storage Checkpoint works” on page 85.
Unlike a disk-based mirroring technology that requires a separate storage space,
Storage Checkpoints minimize the use of disk space by using a Storage Checkpoint
within the same free space available to the file system.
After you create a Storage Checkpoint of a mounted file system, you can also
continue to create, remove, and update files on the file system without affecting
the logical image of the Storage Checkpoint. A Storage Checkpoint preserves not
only the name space (directory hierarchy) of the file system, but also the user data
as it existed at the moment the file system image was captured.
You can use a Storage checkpoint in many ways. For example, you can use them
to:
■ Create a stable image of the file system that can be backed up to tape.
■ Provide a mounted, on-disk backup of the file system so that end users can
restore their own files in the event of accidental deletion. This is especially
useful in a home directory, engineering, or email environment.
■ Create a copy of an application's binaries before installing a patch to allow for
rollback in case of problems.
■ Create an on-disk backup of the file system in that can be used addition to a
traditional tape-based backup to provide faster backup and restore capabilities.
How Storage Checkpoints differ from snapshots
Storage Checkpoints differ from Veritas File System snapshots in the following
ways because they:
■ Allow write operations to the Storage Checkpoint itself.
■ Persist after a system reboot or failure.
■ Share the same pool of free space as the file system.
■ Maintain a relationship with other Storage Checkpoints by identifying changed
file blocks since the last Storage Checkpoint.
■ Have multiple, read-only Storage Checkpoints that reduce I/O operations and
required storage space because the most recent Storage Checkpoint is the only
one that accumulates updates from the primary file system.
Various backup and replication solutions can take advantage of Storage
Checkpoints. The ability of Storage Checkpoints to track the file system blocks
that have changed since the last Storage Checkpoint facilitates backup and
replication applications that only need to retrieve the changed data. Storage
Checkpoints significantly minimize data movement and may promote higher
Storage Checkpoints
About Storage Checkpoints
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