Bent Terp wrote:
On Jan 30, 2008 5:25 PM, Johnny Hughes <johnny@xxxxxxxxxx> wrote:In any event, I can not duplicate the problem with an nfs export on c4 or c5 and connecting with a c5 client, regardless of the kernel using i686.Good point, thanks Johnny! We've verified that here; problem does not occur when mounting a Linux nfs-share, and does occur when mounting a Celerra nfs-share. I've opened a Service Request @ EMC, and will post here again when relevant. Thank you for helping us - with this issue in particular, and with making CentOS happen in general!
You're welcome.There seems to be something about the new kernel that causes many more "client rpc calls" and "nfs v3 client lookups" for some (but not all) operations. I have been able to reproduce (as have others) the issues that seem to cause the problem on i686 and x86_64 regardless of the backend server, however it seems to more pronounced on x86_64 clients.
Whether or not it has a major effect will depend on the volume of individual actions performed per time. The more actions per second, the bigger the impact (it seems).
I did not see a major impact on performance on i686 (15 seconds on a 3.5 min operation), though I did see the issues in nfsstat ... however on x86_64 it did seem to cause more time issues. Also, I was doing one controlled operation, so if many of these where happening at the same time it might have a different impact.
In any event, I have posted an upstream bug to address this issue: https://bugzilla.redhat.com/show_bug.cgi?id=431092 Hopefully we can get it resolved. Thanks, Johnny Hughes
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