> 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
>           rpcmod:maxdupreqs=8192
> Maybe it's too high?

Are you still receiving the original error message your reported
after making these changes? (the "no slots free" error)

If not, then the problem is in the local filesystem.
What you have done is just allowed the NFS server to use the
threads that it can create and not reject with error the incoming


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