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
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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