[Samba] Transfer rates faster than 23MBps?

[Mark Smith]

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