Old SUN NFS performance papers.

Björn Grönvall bg at sics.se
Tue Jan 27 11:20:20 PST 2004

On Sat, 24 Jan 2004 21:14:51 -0500 (EST)
Robert Watson <rwatson at freebsd.org> wrote:

> I haven't done much benchmarking on NFS lately, but something worth
> remembering is that people have spent a lot of time researching and
> optimizing TCP for a variety of connection types, whereas the NFS code
> basically has a static implementation of RPC backoff and flow control that
> hasn't evolved much.

One reason that FreeBSD users experience poor NFSv3/TCP performance is
that the defaults for rsize and wsize is unusually small, only
8k. Solaris and HP-UX defaults to 32k for a good reason. I guess TCP
simply needs a little bit more data to chew on to be efficient.

I tested this on 5.2-CURRENT and found that large file read
performance went up from 56Mbit/s to 80Mbit/s, an improvement by 43%.

I have written a patch that makes FreeBSD use the same defaults as
Solaris and HP-UX. Note that with NFSv3 there is no risk associated
with specifying to large values for [rw]size. The server automatically
limits these values in the fsinfo rpc. Patch is attached.


  _     _                                           ,_______________.
Bjorn Gronvall (Björn Grönvall)                    /_______________/|
Swedish Institute of Computer Science              |               ||
PO Box 1263, S-164 29 Kista, Sweden                | Schroedingers ||
Email: bg at sics.se, Phone +46 -8 633 15 25          |      Cat      |/
Cellular +46 -70 768 06 35, Fax +46 -8 751 72 30   '---------------'
-------------- next part --------------
A non-text attachment was scrubbed...
Name: nfsclient.patch
Type: application/octet-stream
Size: 1835 bytes
Desc: not available
Url : http://lists.freebsd.org/pipermail/freebsd-performance/attachments/20040127/6caa0e2c/nfsclient.obj

More information about the freebsd-performance mailing list