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

Disk Group Split/Join is used to split off snapshot volumes into a separate disk
group that is imported on the OHP host.
Note: As the snapshot volumes are to be moved into another disk group and then
imported on another host, their contents must first be synchronized with the
parent volumes. On reimporting the snapshot volumes, refreshing their contents
from the original volume is speeded by using FastResync.
About point-in-time copy technology
This topic introduces the point-in-time copy solutions that you can implement
using the Veritas FlashSnap™ technology.
Veritas FlashSnap offers a flexible and efficient means of managing business
critical data. It allows you to capture an online image of actively changing data
at a given instant: a point-in-time copy. You can perform system backup, upgrade
and other maintenance tasks on point-in-time copies while providing continuous
availability of your critical data. If required, you can offload processing of the
point-in-time copies onto another host to avoid contention for system resources
on your production server.
The following kinds of point-in-time copy solution are supported by the FlashSnap
license:
■ Volume-level solutions are made possible by the persistent FastResync and
Disk Group Split/Join features of Veritas Volume Manager. These features are
suitable for implementing solutions where the I/O performance of the
production server is critical.
See “Persistent FastResync of volume snapshots” on page 134.
See “Disk group split/join” on page 136.
■ File system-level solutions use the Storage Checkpoint feature of Veritas File
System. Storage Checkpoints are suitable for implementing solutions where
storage space is critical for:
■ File systems that contain a small number of mostly large files.
■ Application workloads that change a relatively small proportion of file
system data blocks (for example, web server content and some databases).
■ Applications where multiple writable copies of a file system are required
for testing or versioning.
See “Storage Checkpoints” on page 137.
■ File level snapshots.
The FlashSnap license also supports the Veritas FlashSnap Agent for Symmetrix.
133Understanding point-in-time copy methods
About point-in-time copy technology