[Lustre-discuss] Resizing OSTs?

[Andreas Dilger]

On 2010-11-14, at 04:28, Andreas Dilger wrote:
> Speaking with my non-Oracle hat on - I have done offline resizing of OSTs on top of LVM many times w/o problems (subject to other OST size limitations of course).  As suggested elsewhere, using the latest Lustre e2fsprogs is important.  Also, as Brian mentions, having a backup is really a good idea.  If you only resize a single OST at a time, it would not need a huge amount of space for the backup.
> 
>> But also, if you have the space to back one up (per the above) you could
>> simply use the information in the other thread I mentioned to go through
>> your OSTs rebuilding them one by one on the larger disks, utilizing all
>> of the space when you do the initial formatting of them.
> 
> Though this would be slower, I've done this on occasion as well if I want to change the configuration of the filesystem (e.g. creating fewer inodes, or chaning other format-time options).  It is possible to use lfs_migrate script to empty out the OST first, if this is possible/safe in your environment, so that the OST can be take offline without impacting the rest of the filesystem.
> 
> Also, in bug 14489 att 15794 there is an untested patch to pass ioctls down from the lustre mountpoint (e.g. /mnt/mdt/lustre-mdt0000) to the underlying ldiskfs filesystem, so that 

... it is possible to run resize2fs on the mountpoint of a Lustre OST to increase the size of the underlying filesystem on-the-fly.

Cheers, Andreas
--
Andreas Dilger
Lustre Technical Lead
Oracle Corporation Canada Inc.