On Sun, 29 Sep 2013, James Harper <james.harper@bendigoit.com.au> wrote:
Actually, revisiting the feature list of BTRFS the 'some point' might be now. Compression seems particularly attractive as that would take some load off of the backup client machines
I'm running Debian Wheezy, so I assume I want the 3.10 kernel from backports.
I don't think that you can ever expect filesystem compression to compete well with application level compression. Filesystem compression is based around the expectation of random access while much application compression is based around entirely compressing large files due to the application/user knowing that random access isn't required. But if you want random access and compression then filesystem compression apparently works well.
The reason I want to do it on the filesystem is that bacula's compression sucks the performance out of the machine being backed up. It has LZO now which is better, but in the little testing I've done, btrfs is faster still. If the end result is a compression ratio that really sucks then I'll revisit it.
I'm not even sure if I have compression enabled on my systems, the data I'm storing on BTRFS isn't going to compress well anyway.
For Debian you want a newer kernel than is available in Wheezy. The Wheezy kernel does work and if you avoid getting the filesystem anywhere near full then it will work well. But later kernels have many bug fixes.
wheezy-backports has 3.10
Don't use BTRFS RAID-5, that's no-where near usable. If you want data integrity and RAID-5 then there is no option other than ZFS at this time.
I'm testing RAID5 now but I can't find anything wrt stability beyond the original post announcing it in 3.8. I'm hoping it is now considered more stable but haven't found anything to back that up yet, so I may be switching to RAID10, then upgrading to RAID5 when it is considered stable. I'll be pulling the power and pulling a disk out on the machine soon anyway to see what happens. Thanks James