[Ocfs2-users] ocfs2 backup strategies

[Uwe Schuerkamp]

Hi folks,

I was wondering what is a good backup strategy for ocfs2 based
clusters. 


Background: We're running a cluster of 8 SLES 10 sp2 machines sharing
a common SAN-based FS (/shared) which is about 350g in size at the
moment. We've already taken care of the usual optimizations concerning
mount options on the cluster nodes (noatime and so on), but our backup
software (bacula 2.2.8) slows to a crawl when encountering directories
in this filesystem that contain quite a few small files. Data rates
usually average in the tens of MB/sec doing "normal" backups of local
filesystems on remote machines in the same LAN, but with the ocfs2 fs
bacula is hard pressed to not fall below 1mb / sec sustained
throughput which obviously isn't enough to back up 350g of data in a
sensible timeframe.

I've already tried disabling compression, rsync'ing to another server
and so on, but so far nothing has helped with improving data rates. 

How would reducing the number of cluster nodes help with backups? Is
there a "dirty read" option in ocfs2 that would allow reading the
files without locking them first or something similar? I don't think
bacula is the culprit as it easily manages larger backups in the same
environment, even reading off smb shares is order of magnitudes faster
in this case, so my guess is I'm missing out some non-obvious
optimization that would improve ocfs2 cluster performance. 

Thanks in advance for any pointers & all the best, 


Uwe 




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