[Samba] Weird Samba upload performance on Gigabit network

David Harrison david.harrison at stress-free.co.nz
Sat Nov 11 01:03:03 GMT 2006

On 11/11/2006, at 6:04 AM, Andrew Morgan wrote:

> 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 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

No the network checks out, all interfaces are running at 1000baseT  
full duplex.
Network performance in general is good for other services, it seems  
the only issue is with client upload rates to the Samba server.

It would appear to be very similar to this issue in terms of the  
hardware and symptoms:

Changing the NIC should resolve the problem and it will give me an  
opportunity to test the card on another system.


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