Veritas Storage Foundation™ 5.0.1 for Oracle RAC Installation, Configuration, and Administrator's Guide Extracts for the HP Serviceguard Storage Management Suite on HP-UX 11i v3

4 Using Storage Checkpoints and Storage Rollback
This chapter contains the following topics:
• “About Storage Checkpoints and Storage Rollback in SGeRAC” (page 31)
• “Using Storage Checkpoints and Storage Rollback for Backup and Restore” (page 31)
• “Determining Space Requirements for Storage Checkpoints” (page 32)
• “Performance of Storage Checkpoints” (page 33)
• “Backing up and Recovering the Database Using Storage Checkpoints” (page 34)
• “Guidelines for Oracle Recovery” (page 36)
• “Using the Storage Checkpoint Command Line Interface (CLI)” (page 37)
• “Examples of Using the Command Line Interface” (page 38)
About Storage Checkpoints and Storage Rollback in SGeRAC
Veritas Storage Checkpoints enable efficient backup and recovery of Oracle databases. The Veritas
Storage Checkpoint feature is available with SGeRAC as part of the Veritas File System package
and is used for the efficient backup and recovery of Oracle databases. Storage Checkpoints can
also be mounted, allowing regular file system operations to be performed or secondary databases
to be started. Review the information on Storage Checkpoints and Storage Rollback and how to
use these technologies through HP Serviceguard for Oracle RAC.
Using Storage Checkpoints and Storage Rollback for Backup and Restore
SGeRAC provides a Storage Checkpoint facility that is similar to the snapshot file system
mechanism; however, a Storage Checkpoint persists after a system reboot. A Storage Checkpoint
creates an exact image of a database instantly and provides a consistent image of the database
from the point in time the Storage Checkpoint was created. The Storage Checkpoint image is
managed and available through the HP Storage Management suite command line interface (CLI).
For more information on creating Storage Checkpoints with the CLI:
See “Creating Storage Checkpoints Using dbed_ckptcreate” (page 39).
A direct application of the Storage Checkpoint facility is Storage Rollback. Because each Storage
Checkpoint is a consistent, point-in-time image of a file system, Storage Rollback is the restore
facility for these on-disk backups. Storage Rollback rolls back changed blocks contained in a
Storage Checkpoint into the primary file system for restoring the database faster.
For more information on Storage Checkpoints and Storage Rollback, see the Veritas File System
Administrator’s Guide.
About Storage Checkpoints and Storage Rollback
A Storage Checkpoint is a disk and I/O efficient snapshot technology for creating a “clone” of a
currently mounted file system (the primary file system). Like a snapshot file system, a Storage
Checkpoint appears as an exact image of the snapped file system at the time the Storage
Checkpoint was made. However, unlike a snapshot file system that uses separate disk space, all
Storage Checkpoints share the same free space pool where the primary file system resides unless
a Storage Checkpoint allocation policy is assigned. A Storage Checkpoint can be mounted as
read-only or read-write, allowing access to the files as if it were a regular file system. A Storage
Checkpoint is created using the dbed_ckptcreate command.
Initially, a Storage Checkpoint contains no data—it contains only the inode list and the block
map of the primary fileset. This block map points to the actual data on the primary file system.
Because only the inode list and block map are needed and no data is copied, creating a Storage
Checkpoint takes only a few seconds and very little space.
About Storage Checkpoints and Storage Rollback in SGeRAC 31