Hello Spencer,

Thursday, June 15, 2006, 11:48:57 PM, you wrote:

SS> On Thu, Robert Milkowski wrote:
>> Hello nfs-discuss,
>>   Sometimes on nfs servers I get below messages and then I have
>>   performance problems. What are they about and what can I do about
>>   this?
>> XXXX  rpcmod: [ID 851375 kern.warning] WARNING: svc_cots_kdup no slots free
>> XXXX  last message repeated 700353 times

SS> This is an error from the NFS server when it attempts to place
SS> a request into the duplicate request cache and finds that
SS> all of the ones in the duplicate request table are "in progress".

SS> The maximum for the duplicate request cache is 1024.

SS> The most effective way to increase the value is /etc/system
SS> and the variable would be: rpcmod:cotsmaxdupreqs 

I set it to 8192 and see some problems with nfsd+zfs - like almost all
threads hanging in ZFS and no actual IOs are happening while I can
issue IOs to the same zfs filesystems locally (see nfsd threads hang
in ZFS on zfs-discuss list).

I did set rpcmod:cotsmaxdupreqs=8192

Maybe it's too high?

Best regards,
 Robert                            mailto:rmilkowski at task.gda.pl

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