[Samba] Very slow transfers to Samba on Ubuntu

[John Du]

My samba server is 3.0.28a running on RHEL 4.

My network is also 100Mbps.  I copy a 100MB file from Windows XP to my 
samba server in about 20 seconds.  Scp the same file from a Linux host 
to the same server takes about the same time.

You may take a look at setting the Windows TCP buffer sizes.  I did not 
change mine though.

Raghu A wrote:
> I tried TCP_NODELAY and it didn't make a difference. I haven't tried
> SO_SNDBUF and RCVBUF, but I will. As the tcpdump shows there is lot of tcp
> window left.
>
> It is not just the server since linux samba client behaves much better. What
> determines SMB packet size?
>
> What is the throughput you get? Is this with an XP/windows client?
>
> Raghu.
>
>
> John Du-4 wrote:
>   
>> Have you looked at adjusting the "socket options" parameter in smb.conf?
>>
>> I use "socket options = TCP_NODELAY SO_SNDBUF=8192 SO_RCVBUF=8192" in my 
>> smb.conf and scp and samba take about the same amount of time to 
>> transfer files from Windows to the samba server.
>>
>> Raghu A wrote:
>>     
>>> There is no disk or CPU bottleneck or virus checking (server is latest
>>> ubuntu). scp at the same time as this transfer can write 3-4 faster to
>>> the
>>> same partition. This is an Atom processor but there is more cpu left.
>>>
>>> To be more specific:
>>>
>>> Why does XP send only 1KB at a time to the server? I think this is pretty
>>> much the culprit. I can send decoded TCP dump of initial SMB handshake if
>>> you are interested. There seems to be some configuration mismatch.
>>>
>>> When I tried a Ubuntu samba client it sends 4KB SMB packets. This helps a
>>> lot with the transfer rate. Btw, looks like most of the CPU consumed by
>>> smbd
>>> is per packet.. so inceasing this packet size reduces CPU as well.
>>>
>>> Raghu.
>>>
>>>
>>> Ben Tyger wrote:
>>>   
>>>       
>>>> What type of file processors are you running along with samba?. Are you
>>>> running the virus checking plugin or VFS(recycle bin)? Virus checking is
>>>> very cpu and disk I/O intensive these can really slow down a samba
>>>> server. I can't expect VFS is all that cheap either when moving big
>>>> files.
>>>>
>>>> Raghu A wrote:
>>>>     
>>>>         
>>>>>> I mounted a samba volume on XP. XP and Ubuntu are connected over
>>>>>> 100Mbps
>>>>>> ethernet (router).
>>>>>>
>>>>>> I am writing a 4GB file from XP to Ubuntu and the transfer is
>>>>>> extremely
>>>>>> slow : only around 1-1.5 MB/s.
>>>>>>         
>>>>>>             
>>>>     
>>>>         
>>>   
>>>       
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>>     
>
>