[CentOS] MySQL issues with kernel-2.6.18-53.1.6.el5.x86_64.rpm

[Johnny Hughes]

Bent Terp wrote:
> On Jan 30, 2008 5:25 PM, Johnny Hughes <johnny at centos.org> 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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