FreeBSD 9.0 and NFS async

[Johan Hendriks]

Rick Macklem schreef:
> Johan Hendriks wrote:
>> Hello all.
>>
>> I used to use async on my 8.x nfs servers!
>> On the FreeBSD 9.0 server i can not do it through the old 8.x sysctl.
>>
>> Is there an other way to set async on FreeBSD 9.x
>>
> You have two choices:
> 1 - Apply this patch to your NFS server's kernel sources and then set
>      vfs.nfsd.async=1
>      http://people.freebsd.org/~rmacklem/async.patch
>
> 2 - switch to using the old server by setting
>      oldnfs_server_enable="YES"
>      in your /etc/rc.conf and then setting the sysctl.
>
> I'll assume that you realize that doing this violates the NFS RFCs because
> it runs your server in a way where there is a risk of data loss (that the
> client won't know to re-write) when the server crashes.
>
> rick
>> regards,
>> Johan Hendriks
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Yes i do know the risk.

The thing is we want a dataset shared to a ESXi client using NFS.
I use NFS for my normal usage, (sharing ports tree and so on.) but now 
we want to use it to share a ZFS dataset for a ESXi client.
We use iscsi now, but this way we miss some zfs goodies. like 
snapshots(not a zvol) and most important, we can reach the files directly.

But with a virtual machine shared over NFS i get horrible performance.
If i copy a file to whatever virtual machine from a windows client 
shared with iscsi , i get arround 80Mb per second (in the windows copy 
window) almost at a steady pace. we are really pleased with that. !!
If i copy a virtual machine to the NFS share, fire it up, and do a file 
copy, it never gets higher than 50 Mb and it sometimes drop to 1 Mb then 
goes to 20 back to 10 and so on.
Also the machines feels sluggish in performance.

Are there other less dangerous things i can try to boost performance?

regards,
Johan Hendriks