[Samba] Performance: Samba 3 vs. Windows 2003

[Alexander Lazarevich]

Samba guru's:

Our Samba 3 network performance is half that of Windows 2003 Server. I 
really want to stay with samba/unix, but half the performance? I'm hoping 
someone can point me in the right direction so we can keep using 
samba/unix. I'll try to give as much detail without giving pages and 
pages of benchmark numbers. If someone wants to see numbers, I'll send 
them:

Fileserver is Dell PE2600, Dual Xeon 18GHz, 2GB memory, Gig NIC. System 
is dual boot RHEL3-AS with an ext3 filesystem and Windows 2003 Server 
with NTFS. The fileserving disk is a SATA-SCSI RAID enclosure. Bonnie++ 
and iozone both show that the RAID enclosure can do 80MB/sec writes and 
40MB/sec reads on the ext3 in linux. Benchmarks in windows 2003 are very 
similar. Why it gets faster writes than read, I don't know, and I don't 
care right now. What I'm worried about is our samba network performance.

Clients are Windows XP/2K/NT4 pro with all patches installed and Gig NICs. 
All the clients can netperf to the server at 60+MB/sec, some even faster. 
No collisions on the NICs, nothing wrong with the network. There is a 
cisco Gig switch inbetween the client and the server as well.

Here is the bottom line:

When the server is running samba 3, the clients get 12-13MB/sec.

When the server is running windows 2003, the clients get 24-26MB/sec.

Keep in mind the server hardware is exactly the same, the only thing I 
change is the software. Windows 2003 beets up Samba 3, hands down.

However, all this testing is done by just drag and drop, and looking at 
the clock to time it. Not the best way to do it, but I don't know of 
another way now, suggestions welcome. The difference is obvious and 
consistent: 500MB file in samba 3 writes to disk in 42 seconds, but writes 
to windows 2003 disk in 21 seconds. I can produce the same results on all 
of our clients any time of the day.

I've tried changing the smb.conf socket options (TCP_NODELAY, SO_SNDBUF, 
etc.) to 65523, 242xxx, whatever. /etc/init.d/smb restart, then try again. 
No change in performance whatsoever. Still 12-13MB/sec. I've also set 
other options in smb.conf, such as xmit, write size, read size, but 
nothing seems to change the fact that samba 3 can't do more than 
12-13MB/sec.

I've also searched the list, and found some people had success in 
performance issues by changing the SO_SNDBUF, but they didn't list any 
benchmark numbers. Maybe they were happy with 12-13MB/sec, but I'm not, 
especially if something else can get 25MB/sec.

Any input is welcome.

Alex
---                                                               ---
   Alex Lazarevich | Systems Administrator | Imaging Technology Group
    Beckman Institute | University of Illinois | www.itg.uiuc.edu
---                                                               ---