Testing volumes for FlashSnap
Before you run an alternate client backup with the FlashSnap snapshot method, test your FlashSnap volume configuration as described in this section. You must ensure that the disk(s) containing the volume can be moved (deported and imported) to the alternate client without errors.
For instance, the backup disks cannot be split off into a new disk group and deported, if the disks containing the backup volumes contain some part of a volume that has another part on a disk that is not in the backup disks. Deporting a disk group means disabling access to that disk group.
See the Volume Manager Administrator's Guide for more information on deporting disk groups.
The following steps are described in more detail in the Veritas FlashSnap Point-In-Time Copy Solutions Administrator's Guide.
To test volumes for FlashSnap on UNIX
On the primary host:
vxassist -g diskgroup addlog volume logtype=dco
Enable FastResync on the volume:
vxvol -g diskgroup set fastresync=on volume
vxassist -g diskgroup -b snapstart volume
Create a snapshot volume from the primary volume:
For disk groups that were created with VxVM 5.x:
vxassist -g diskgroup snapshot volume snap_volume
Note:
Choose a volume name that is fewer than 15 characters. Volume names are prefixed or suffixed with characters, which increases the volume name. Lengthy volume names can cause snapshot jobs to fail.
For disk groups that were created with VxVM 4.x:
vxsnap -g diskgroup snapshot volume snap_volume
For disk groups that were created with VxVM 3.x:
vxassist -g diskgroup snapshot volume snap_volume
Move the disks containing the snapshot volume to a separate (split) disk group:
vxdg split diskgroup split_diskgroup snap_volume
If the volume has not been properly configured, you may see an error similar to the following:
host-name# vxdg split lhdvvr lhdvvr_split SNAP-emc_concat vxvm:vxdg: ERROR: vxdg split lhdvvr lhdvvr_split failed vxvm:vxdg: ERROR: emc_dis05 : Disk moving, but not all subdisks on it
Re-examine the layout of the disks and the volumes that are assigned to them, and reassign the unwanted volumes to other disks as needed.
Consult the Veritas FlashSnap Point-In-Time Copy Solutions Administrator's Guide for examples of disk groups that can and cannot be split.
vxdg deport split_diskgroup
On the secondary host:
After this test, you must re-establish the original configuration to what it was before you tested the volumes.
Deport the disk group on the alternate client.
Import the disk group on the primary client.
Recover and join the original volume group.
To test volumes for FlashSnap on Windows
On the primary host:
If not already done, create a snapshot mirror:
vxassist snapstart \Device\HarddiskDmVolumes\diskgroup\volume
Create a snapshot volume from the primary volume:
vxassist snapshot \Device\HarddiskDmVolumes\diskgroup\volume DrivePath=C:\Temp\Mount SNAP-VolumeMove the disks containing the snapshot volume to a separate (split) disk group.
The disk group is also deported after this command completes:
vxdg -g DskGrp -n SPLIT-DskGrp split \Device\HarddiskDmVolumes\diskgroup\snap_volume
On the secondary host:
Rescan to make the deported disk group visible on the secondary host:
vxassist rescan
Import the disk group that was deported from the primary:
vxdg -g split_diskgroup import
Assign the snapshot volume to an empty NTFS directory.
This example uses
C:\Temp\Mount.vxassist assign \Device\HarddiskDmVolumes\split_diskgroup \snap_volume DrivePath=C:\Temp\MountIf these commands execute successfully, the volume setup is correct.