Thursday, December 22, 2005

Veritas Checkpoints -

SNAPSHOTS are a point in time copy of a filesystem.

mount –F vxfs –o snapof=origfs[,snapsize=size] destination snap_mount_point

mount –F vxfs –o remount, snapof=origfs[,snapsize=size] destination snap_mount_point

umount snap_mount_point

Checkpoints are still better, they are persistent across a reboot and utilise fewer resources.

Primer by Par Botes

Here is a quick primer on checkpoints: (can you tell I really think
should be used instead of snapshots... :)

Checkpoints take
fewer resources than snapshots, they are persistent, you can
independently write to a checkpoint and they will survive a reboot.

Having said all of that... Both of them can handle multi terabyte
filesystem. Checkpoints will do it better and with fewer resource

Create checkpoint:
fsckptadm -n create "a_name" /from_running_filesystem

List checkpoints:
fsckptadm list /from_running_filesystem

Mount checkpoint (default is readonly):
(note that each checkpoint get a pseudo /dev/vx/dsk/dg/ name)
mount -F vxfs -o ckpt=a_name /dev/vx/dsk/diskgroup/volname:a_name
Mounting it read/write:
mount -F vxfs -o ckpt=a_name,rw /dev/vx/dsk/diskgroup/volname:a_name

Umounting the checkpoint:
Umount /checkpoint_mount

Page 68 and onwards in the vxfs administration guide is a really good
read on checkpoint functionality.


This was posted by Par on the veritas mailing list.


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