[CentOS] LVM + XFS + external log + snapshots

Fri Jun 21 22:12:04 UTC 2013
aurfalien <aurfalien at gmail.com>

On Jun 21, 2013, at 2:58 PM, Joseph L. Casale wrote:

>> So I have an XFS file system within LVM  which has an external log.
>> A snapshot volume is created w/o issue;
>> But when i try to mount the file system;
>> mount: /dev/mapper/vg_spock_data-datasnapshot already mounted or /snapshot busy
> So the filesystem was built requiring an external log device?
> Let me guess, the original block device is still mounted and accessing its log device?

Bingo, you got it.

I did this for speed.

The log device is on a pair of mirrored SSD drives I had lying around.

Might as well put em to use.

I have a feeling that freezing the XFS filesystem while a snapshot is made is the way to fix this.

However while I have tested freezing and XFS volume, I am a little shy on doing it on a live production system.

I'll wait until the weekend midnight.

It should be fast;

1) freeze
2) snap shot it
3) mount the snap shot
4) unfreeze
5) do my rsnapshot
6) then unmount and remove the snap shot volume

What do you think?

- aurf