[Samba] Transfer rates faster than 23MBps?

Mark Smith msmith at customflix.com
Thu Sep 21 17:27:11 GMT 2006

I wanted to follow up to my email to provide at least a partial answer 
to my problem.

The stock RedHat AS4-U3 Samba config has SO_SNDBUF and SO_RCVBUF set to 
8k.  With this value, I can transfer a 1GB file in about 70-75 seconds, 
about 14MBps.  If I increase those buffers to their max value of 64k, 
that same 1GB file transfers in 45-50 seconds, about 23MBps.

That is the _ONLY_ configuration value I've found that made any 
difference in my setup.  All the other tweaks I'd done, when removed, 
seemed to make no difference at all.  I was playing with oplocks, 
buffers, max xmit sizes, you name it.  But the socket option buffers was 
the only thing that made a difference.

I'm still looking for more speed.  I'll report if I find anything else 
that helps.

In response to Jeremy's suggestion of using smbclient, I ran a test from 
a Linux client using smbclient and it reported a transfer rate of 
21MBps, about the same as a normal smbfs mount.  I haven't tried porting 
smbclient to Windows yet, and probably won't until we get more info on 
what the server is doing.

Thanks everyone.


Mark Smith wrote:
> We use SMB to transfer large files (between 1GB and 5GB) from RedHat AS4 
> Content Storage servers to Windows clients with 6 DVD burners and 
> robotic arms and other cool gadgets.  The servers used to be Windows 
> based, but we're migrating to RedHat for a host of reasons.
> Unfortunately, the RedHat Samba servers are about 2.5 times slower than 
> the Windows servers.  Windows will copy a 1GB file in about 30 seconds, 
> where as it takes about 70 to 75 seconds to copy the same file from a 
> RedHat Samba server.
> I've asked Dr. Google and gotten all kinds of suggestions, most of which 
> have already been applied by RedHat to the stock Samba config.  I've 
> opened a ticket with RedHat.  They pointed out a couple errors in my 
> config, but fixing those didn't have any effect.  Some tweaking, 
> however, has gotten the transfer speed to about 50 seconds for that 1GB 
> file.
> But I seem to have hit a brick wall; my fastest time ever was 44 
> seconds, but typically it's around 50.
> I know it's not a problem with network or disk; if I use Apache and HTTP 
> to transfer the same file from the same server, it transfers in about 15 
> to 20 seconds.  Unfortunately, HTTP doesn't meet our other requirements 
> for random access to the file.
> Do you folks use Samba for large file transfers at all?  Have you had 
> any luck speeding it up past about 23MBps (the 44 second transfer 
> speed)?  Any help you may have would be fantastic.  Thanks.
> -Mark

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