Veritas Storage Foundation 5.0 for Oracle RAC Configuration Guide Extracts for HP Serviceguard Storage Management Suite, Second Edition, May 2008

Using FlashSnap for Backup and Recovery

Preparing Hosts and Storage for Database FlashSnap

Chapter 5

The example procedure is for existing volumes without existing snapshot plexes or

associated snapshot volumes. In the example procedure, volume_name is the name of

either a volume or a volume set.

To create a snapshot mirror of a volume or volume set

1. To prepare the volume for being snapshot, use the vxsnap prepare command:

# vxsnap -g diskgroup prepare volume \

alloc="storage_attribute ..."

The vxsnap prepare command automatically creates a DCO and DCO volumes and

associates them with the volume, and enables Persistent FastResync on the volume.

Persistent FastResync is also set automatically on any snapshots that are generated

from a volume on which this feature is enabled.

For enabling persistent FastResync on a volume in VxVM 4.1, either from the

command line or from within a script, use the vxsnap prepare command as

described above.

2. To verify that FastResync is enabled on the volume, use the vxprint command:

# vxprint -g diskgroup -F%fastresync volume_name

This returns on if FastResync is on. Otherwise, it returns off.

3. To verify that a DCO and DCO log volume are attached to the volume, use the

vxprint command:

# vxprint -g diskgroup -F%hasdcolog volume_name

This returns on if a DCO and DCO log volume are attached to the volume.

Otherwise, it returns off.

4. Create a mirror of a volume:

Usage Notes • Create a separate disk group for Oracle database-related files.

• Do not share volumes between Oracle database files and other

software.

• ORACLE_HOME cannot be included in the snapshot mirror.

• Resynchronization speed varies based on the amount of data

changed in both the primary and snapshot volumes during the

break-off time.

• Do not share any disks between the original mirror and the

snapshot mirror.

• Snapshot mirrors for datafiles and archive logs should be created

so that they do not share any disks with the data of the original

volumes. If they are not created in this way, the VxVM disk

group cannot be split and, as a result, Database FlashSnap will

not work.

NOTE: Database FlashSnap commands support third-mirror

break-off snapshots only. The snapshot mirror must be in the

snapdone state.

Table 5-1 vxsnap Command for Snapshot Mirror Notes (Continued)