[Samba] Weird Samba upload performance on Gigabit network

[Andrew Morgan]

On Fri, 10 Nov 2006, David Harrison wrote:

> On 10/11/2006, at 12:22 PM, John Drescher wrote:
>
>> On 11/9/06, David Harrison <david.harrison at stress-free.co.nz> wrote:
>> - BUT OSX Tiger to Samba 3.0.23C (Suse 10) file transfers operate at
>> 1-2meg/second which is well down from expected performance.
>> 
>> The strange thing is if I begin a file transfer from OSX Tiger to
>> Samba and in a terminal window on OSX begin an SCP copy operation to
>> the same Suse server the file transfer speed of Samba jumps up to
>> gigabit level speeds. As soon as the SCP copy operation is stopped
>> the Samba file transfer process drops to 1-2meg/second again.
>> 
>> Looking at your numbers I believe that you have both network and samba 
>> problems.
>> 
>> Can you run netperf or do some nfs testing?
>> 
>> Today I ran it and found out a few of my servers (using nvidia mobo 
>> adapters) although the gigabit light was on the nic and the switch the 
>> adapter was not transfering at gigabit speeds.  I did a nfs test like the 
>> following:
>> 
>> dd if=/dev/zero of=/mnt/remoteserver/test.dat bs=16k count=16k
>> 
>> and got around 10MB/s which is only 100mbit speeds. On netperf I verified 
>> that my maximum transfer rate was around 94mbit/s so I googled a bit and 
>> then ended up upgrading my kernel to 2.6.18 and then did the same test and 
>> I got 109 MB/s on netperf and on the nfs test above I got 43MB/s and after 
>> setting nfs to asynchronous mode I got 57MB/s.
>> 
>> John
>
> I've updated the Suse box to the 2.6.18.2 kernel with no effect.
> I'm not in a position to run NFS tests on the machine but I'm guessing it is 
> the network card (low-end Netgear with the r8169 driver).
> To (hopefully) fix the problem for good I've ordered a decent gigabit card 
> that by the looks of it has good Linux support.
> I'd rather spend the money than continue messing with a card/driver that 
> according to Google has some underlying performance issues :-)

Have you verified that the duplex settings on the network switch and the 
Suse server are the same?  If you have half duplex on the Suse server and 
full duplex on the network switch, you could get the behavior you 
describe.

 	Andy