[Ocfs2-users] What could cause slow down betwen OCFS2 1.2.9 and 1.4.4

[Ulf Zimmermann]

We upgraded our production database cluster (6 node) from EL4 Update 5 to EL5 Update 5, including upgrading OCFS2 from 1.2.9 to 1.4.4.

We are now noticing slowdown of batch jobs in Oracle, while hotbackup runs faster. One thing we saw is that journal mode changed from write-back to ordered, as we don't specify journal mode during mount. Oracle sees this as slowdown based on higher IO latency, going from 6-8ms to 13-15ms for single block IO. Total IO throughput has dropped. 

Can this be caused by the journal mode being ordered?

Ulf.