[ale] Slow NFS Speed?

[Michael H. Warfield]

On Thu, 2011-09-15 at 10:43 -0400, David Tomaschik wrote: 
> At work, we have an OS X 10.5 NFS server with a Ubuntu Server 10.04
> client.  (Among others.)  We're running backups via NFS using Amanda,
> and the backups seem to be pegging at exactly 100Mbit/s.  Both
> machines are connected via GigE, full-duplex.  (Confirmed via mii-tool
> and system preferences.)

> I can read from the storage array on the XServe at ~200MB/s via dd.
> Additionally, Amanda can read from clients remotely (SSH transport) at
> 400-500 Mbit/s, so it doesn't seem to be an issue with the backup
> server.

What's your "write speed", though (through both NFS and SSH).
Unfortunately, NFS is notorious for this with write speeds often being
significantly slower than read speeds (2:1 or even 3:1 not uncommon).
NFS locking can have some impact.

> I've tried tweaking NFS rsize with no noticeable impact.  Any other
> hints to improve NFS performance?  Anyone with experience with OS X as
> an NFS host?  Most of the information I find online is OS X as an NFS
> client.

That could be a real challenge.  Like I say, NFS has been known for this
as long as I can remember and that goes all the way back to SunOS 3.x on
68020 processors in the 80's.  Do you know what version NFS is in use?
Linux 2.6 supports versions 2, 3, and 4.  Is the NFS share being
exported "SYNC" or "synchronous"?  That's the default behavior under
Linux, afaik.  I don't know under OS X.  IAC, asynchronous can be much
faster but can be riskier.

Might read this over, particularly the performance section.

http://nfs.sourceforge.net/

> -- 
> David Tomaschik, RHCE, LPIC-1
> System Administrator/Open Source Advocate
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> http://systemoverlord.com
> david at systemoverlord.com
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Michael H. Warfield (AI4NB) | (770) 985-6132 |  mhw at WittsEnd.com
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