[Samba] Strange Performance Issue / concurrent clients -> very very slow

[Götz Reinicke]

Hi,

recently I installed a new GBit connected iSCSI Storage to one of our
fileservers. Redhat EL Linux 5.7 samba3x-3.5.4-0.83.el5, kernel
2.6.18-238.19.1.el5PAE, Dell Poweredge 1750, dual Xeon.

The transfer speed is very very different, depending on the method I
use. Currently I'm the only user accessing that server and there is low
network traffic.

I know, that there are some overheads etc. which influence the speed.

My Test Client is a Macbook pro  and a Mac Pro (OS X 10.6.x each,
connected by GBit wired lan)

I copy a couple of 30 MB files and in an other test files of 1GB.

Transferspeed for ftp is about 85 MB/s, scp about 25 MB/s, samba 30 MB/s.

So the 'raw' speed is o.k. for me, more that 30 MB would be nice.

BUT the most confusing thing is, as soon as I copy files from two
clients at the same time to my samba share, the performance drops to 5
MB/s for each client. So 10 MB/s.

Transferring from two ftp clients is about 40 MB/s per client.

Currently I use 'socket options = TCP_NODELAY SO_RCVBUF=8192
SO_SNDBUF=8192 IPTOS_LOWDELAY'

Dose anybody has an explanation for such a poor performance? Any tunig
tips or hints? Everything is welcome.

	Thanks and best regards. Götz

-- 
Götz Reinicke
IT-Koordinator

Tel. +49 7141 969 420
Fax  +49 7141 969 55 420
E-Mail goetz.reinicke at filmakademie.de

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