Reclaim space puredisk pool

[itlicenseadmin]

We have mapped many volume group in RHEL to create large size of puredisk pool. so far we have utilized only 20% of space to store backup image and remaining are no use at all.

We want to reclaim some of the space lets say 50% space from puredisk pool. Is there any out of box solution in netbackup.

I have identified xfsdump to trasnfer to backup images to new location then unmap vg and lv and present it agian, but this procedure involves risk and long prcedure. We can present some small vg if netbackup allow to migrate from one puredisk pool to another.

[andrew_mcc1]

There's nothing out of the box as far as I know. Duplication to a new Deduplication Pool pool is possible but only if it is on a new Media Server. As you say xfsdump & xfsrestore should work assuming you are using XFS but you will need additional temporary storage and of course NetBackup needs to be shutdown.

If retentions are not long, you could stand up a new Media Server and Deduplication Pool and let images expire on the old one and then decommission the original pool.

Good luck, Andrew

[Nicolai]

This is more a OS issues than Netbackup. Netbackup uses the files system configured, it can't do volume management.

If the LUN's assigned are thin provisioned, you actual don't use the allocated space on array level.

You can do all sort of volume management as long as you don't touch the file system. changing the file system content will bring you in the un-supported category fast.

For the experinced Linux admin - you can rsync all file system content from one vg/fs to another, but that operation may be very time consuming depending on MSDP pool size. The MSDP pool need to be offline while the operation last.

Also makre sure you got the discard mount option listed in /etc/fstab for space reclamation to work 

http://xfs.org/index.php/FITRIM/discard

[Mouse]

Depending on your layout and how many PVs are used and whether they are at all used, you may first try to remove all PVs which are unused, apologies if stating the obvious. Then, you can choose PVs with least PEs used on them and consoldate those to other PVs with pvmove, this works online. Read the man page for pvmove it's quite descriptive. Then remove the unused PVs.

Or, if you have extra storage that can accommodate the entire used space in the VG, just create a LUN and a PV on top of it, join it to the VG, move all PEs and remove all old PVs from the VG.

I'd not bother with file system commands if it can be done using LVM, as it will be fully transparent and can be done online.

As with any disk operations, a backup of the pool (replica or tape duplication) could be handy.

[Nicolai]

Apparently it is not possible to shrink a XFS file system. So you are basically looking into copying off data the file system, creating the new file system and copying data back.