FreeBSD 9.0 and NFS async

Rick Macklem rmacklem at uoguelph.ca
Wed Dec 14 00:35:18 UTC 2011


Peter Maloney wrote:
> On 12/13/2011 05:18 PM, Johan Hendriks wrote:
> > 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
> >>> _______________________________________________
> >>> freebsd-fs at freebsd.org mailing list
> >>> http://lists.freebsd.org/mailman/listinfo/freebsd-fs
> >>> To unsubscribe, send any mail to
> >>> "freebsd-fs-unsubscribe at freebsd.org"
> > 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.
> >
> That is interesting. I am doing the same thing (and settling for the
> horrible 5-9MB/s writes right now with a decent ZIL that goes 65 MB/s
> with any other NFS sync client). But without any NFS settings, I found
> I
> can simply run:
> # zfs set sync=disabled tank/esxidatasetname
> with the same file integrity sacrifice Rick mentions above.
> 
> I found that
> vfs.nfsd.async=1
> doesn't actually do anything for me (8.2-STABLE Sept 29th).

This sysctl won't exist unless you apply the patch (that isn't even
in head yet).

For FreeBSD8.n, the default server is the old one and
  vfs.nfsrv.async=1
would be the sysctl. (If that was what you meant, then don't worry
about the above comments, rick)

> 
> > Are there other less dangerous things i can try to boost
> > performance?
> >
> > regards,
> > Johan Hendriks
> >
> >
> >
> >
> >
> >
> >
> > _______________________________________________
> > freebsd-fs at freebsd.org mailing list
> > http://lists.freebsd.org/mailman/listinfo/freebsd-fs
> > To unsubscribe, send any mail to
> > "freebsd-fs-unsubscribe at freebsd.org"
> 
> 
> --
> 
> --------------------------------------------
> Peter Maloney
> Brockmann Consult
> Max-Planck-Str. 2
> 21502 Geesthacht
> Germany
> Tel: +49 4152 889 300
> Fax: +49 4152 889 333
> E-mail: peter.maloney at brockmann-consult.de
> Internet: http://www.brockmann-consult.de
> --------------------------------------------
> 
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