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

Götz Reinicke goetz.reinicke at filmakademie.de
Fri Oct 28 09:32:33 MDT 2011

Hi José,

no, the iSCSI Storag is on a separate collision domain. The file Server
has two NICs.

And from the test speed you can see, that I can get about 90 MB/s form
my client to ths storage through the server:

Mac ---gbitlan--- switch ---gbitlan--- fileserver ---gbitlan--- iSCSI

	cheers . Götz

Am 28.10.11 17:24, schrieb José Guzmán:
>  Is the new GBit iSCSI storage connected on the same collision domain as
> the other machines?
>  If so, you may be hitting the limit of the switch. Try separating iSCSI
> from the rest of the network with another switch, or at least a separate
> Greetings
>  José
> On 10/28/2011 10:04 AM, Götz Reinicke wrote:
>> 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
>> 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

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

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