OK, I'll top post.
I can't let this stand unanswered.
I ran a LOT of tests with gigabit copper and windows machines. I never
did better than 40 seconds per gig. That was with the Intel cards
configured for maximum cpu utilization. 80-90% cpu for 40 sec per gig.
On windows. Uploads went half as fast. Asymetric. Of course I only
had 32 bit PCI, 2.5Gig processor motherboards with 45MBps drives.
Which leads me to my point. One can't rationally compare performance of
gigabit ethernet without talking about hardware on the platforms. I
wouldn't think you'd have overlooked this, but one can bump up against
the speed of the disk drive. Raid has overhead. Have you tried
something like iostat? Serial ATA? I seem to recall the folks at
Enterasys indicating 300Gbps as a practical upper limit on copper gig.
Are you using fiber? 64 bit PCI? Who made which model of the network
card? Is it a network card that's well supported in Linux? Can you
change the interrupt utilization of the card? What's the CPU
utilization on the Redhat machine during transfers?
I don't have specific answers for your questions, but one can't just say
this software product is slower on gigabit than the other one without
talking hardware at the same time.
I have lots of memory. I use these configurations in sysctl.conf to up
the performance of send/recieve windows on my systems. There's articles
out there. I don't have historical references handy.
YMMV.
net.core.wmem_max = 1048576
net.core.rmem_max = 1048576
net.ipv4.tcp_wmem = 4096 65536 1048575
net.ipv4.tcp_rmem = 4096 524288 1048575
net.ipv4.tcp_window_scaling = 1
Regards, Doug
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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