Terrible NFS4 performance: FreeBSD 9.1 + ZFS + AWS EC2

[Rick Macklem]

Berend de Boer wrote:
> >>>>> "Rick" == Rick Macklem <rmacklem at uoguelph.ca> writes:
> 
> 
>     Rick> After you apply the patch and boot the rebuilt kernel, the
>     Rick> cpu overheads should be reduced after you increase the
>     value
>     Rick> of vfs.nfsd.tcphighwater.
> 
> Do I need to umount the share? Restart something after changing this
> value?
> 
I think you can safely change it "on the fly". It simply defines how
large the DRC cache can grow before the nfsd thread will try to trim
it down. The default of 0 means "trim every RPC", which keeps it at a
minimal size, but can result in significant CPU overhead.

rick

> --
> All the best,
> 
> Berend de Boer
> 
> 
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