On Wed, Jan 18, 2012 at 8:40 AM, Wayne <[email protected]> wrote: > We have set up a new cluster and are now seeing pdflush processes pegged at > 100% cpu during compaction. Is this normal? It sometimes "looks" like > pdflush is pegged at 100% for quite a while and the java cpu usage goes > down as if it is waiting on it to finish. We are using 0.90.4 on centos 5.5 > with no swap. Is this a linux kernal issue due to no swap? This cluster is > the first time we have ever seen this but we are running a slightly newer > kernal than other cluster where we did not see this. >
I've not noticed it Wayne (can't say I was particularly on the lookout for it but I suppose I'd have seen a 100%pdflush if it was going on). > Any ideas? Should we be worried about this? Is/can pdflush really be a > bottleneck to disk writes? > Could you try older kernel on one of the cluster members and see if it still 100%s? What about the pdflush tunings on the two clusters? Are they the same? (I was looking at this page: http://www.westnet.com/~gsmith/content/linux-pdflush.htm) St.Ack
