[clug] samba performance [actually cifs is slow]

Eyal Lebedinsky eyal at eyal.emu.id.au
Tue Apr 28 12:42:01 GMT 2009

If I cannot sort this out with help from the list then I will report to
Steve French, but only after I look a bit deeper.

I did not mount with special options but used mostly defaults:
//files/data2  /data2  cifs  user=GUEST,guest,rw,uid=eyal,gid=eyal 0 0

and the /proc/mounts line shows:
//files/data2 /data2 cifs rw,mand,relatime,unc=\\files\data2,username=,uid=500,gid=500,acl,rsize=16384,wsize=57344 0 0

server kernel is (my vanilla build)
and client is (recent f9)

wire [109 MB/s]
[eyal at e4 ~]$ rsh e7 dd if=/dev/zero bs=1MB count=128 >/dev/null
128+0 records in
128+0 records out
128000000 bytes transferred in 1.123810 seconds (113898261 bytes/sec)

smbclient [84 MB/s]
[eyal at e4 ~]$ smbclient -N //e7/data2 --command="get tmp/128MB"
Domain=[LEBEDINSKY] OS=[Unix] Server=[Samba 3.0.14a-Debian]
getting file \tmp/128MB of size 134217728 as tmp/128MB (85892.5 kb/s) (average 85892.5 kb/s)

cifs [26.9 MB/s]
[eyal at e4 ~]$ dd if=/data2/tmp/128MB of=/dev/null bs=16MB
8+1 records in
8+1 records out
134217728 bytes (134 MB) copied, 4.98954 s, 26.9 MB/s

BTW, the mount always says
   CIFS VFS: Negotiating Unix capabilities with the server failed.  Consider mounting with the Unix Extensions
   disabled, if problems are found, by specifying the nounix mount option.
but adding this option does not change the bandwidth.


tridge at samba.org wrote:
> Hi Eyal,
>> I now confirmed that smbclient gives a reasonable performance, it is the cifs
>> mount that is slow.
> You haven't mentioned what cifs mount options you have used. What is
> shown in /proc/mounts for the filesystem? What kernel?
> If you've found a real performance problem for the cifsfs filesystem
> client then Steve French may want to know about it (he is the cifsfs
> maintainer). First you should get a wireshark sniff though and see if
> there are any obvious reasons that show up.
> cifsfs should easily be able to saturate the wire at gigabit speeds,
> unless you have a high latency network.
> Cheers, Tridge

Eyal Lebedinsky	(eyal at eyal.emu.id.au)

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