samba - Oct 1998 - Performance tips for heavily loaded servers

Does nayone have a collection of performance tips for heavily loaded 
samba servers?

I have a server that routinely has 45-90 connections and just runs really 
poorly. We've thrown more memory at it w/ some benefit, but not 
significant. 

This is on a linux 2.0.35 based machine.

Does anyone have any suggestions?

-- Nathan

------------------------------------------------------------
Nathan Neulinger                       EMail:  nneul@umr.edu
University of Missouri - Rolla         Phone: (573) 341-4841
Computing Services                       Fax: (573) 341-4216

Nathan Neulinger wrote:
> Does nayone have a collection of performance tips for heavily loaded
> samba servers?
Here's what we've done.
> I have a server that routinely has 45-90 connections and just runs really
> poorly. We've thrown more memory at it w/ some benefit, but not
> significant.
We serve ~350-500 clients with userdata and applications from a single server
(Sun E4000, 4 nics, 4 scsi cards).

The biggest bottlenecks usually are disks and memory.

Try to keep userdata on striped disks (fast to write and read) and
applications on mirrored disks (fast to read, slow to write). Put swap on a
disk of it's own.

Try to keep memory at about 5MB/client.

Keep samba logs at a minimum, unless you need to debug. This usually is
a big perfomance downer for RedHat machines. The standard logging is
set by client and with lots of clients you get lots of log files. (change
"log
file = log.smb.%m" to "log file = log.smb")

At compile time put in -DUSE_MMAP if you can spare some extra memory.
This gave a boost of ~40% for us.

Also look at your network, try to keep the samba traffic away from
your router, instead put in a network card on as many subnets
you can (atleast the ones with most traffic). 
> This is on a linux 2.0.35 based machine.
A PC. Get a network card with busmastering get a good scsi card and some fast
scsi disks.

/mvh Kalle Kiviaho - kivi@ios.chalmers.se

> Nathan Neulinger wrote:
> 
> > I have a server that routinely has 45-90 connections and just runs
really
> > poorly. We've thrown more memory at it w/ some benefit, but not
> > significant.
> 
> We serve ~350-500 clients with userdata and applications from a single
server
> (Sun E4000, 4 nics, 4 scsi cards).
> 
For the record: 330 Win95 clients being served from 2 DEC 2100A's and 1
DEC 1000A (applications only)..
> The biggest bottlenecks usually are disks and memory.
> 
This is definiately the *not* the case at my site.  CPU appears to be the
biggest problem.  Memory gets chewed, but never gets exhausted.  Discs are
fairly idle as the UBC (Unified Buffer Cache) that the OS provides get
upwards of 95% hits.
> At compile time put in -DUSE_MMAP if you can spare some extra memory.
> This gave a boost of ~40% for us.
> 
Done this.

Any other tips, especially for serving applications?


Rob Naccarato           "Civilized men are more discourteous than savages
Sys Admin               because they know they can be impolite without
Sheridan College        having their skulls split, as a general thing."
Oakville, Ont. Canada                      - Robert E. Howard

Nathan wrote, 
> Does nayone have a collection of performance tips for heavily loaded 
> samba servers?
>
> I have a server that routinely has 45-90 connections and just runs really 
> poorly. We've thrown more memory at it w/ some benefit, but not 
> significant. 
>
> This is on a linux 2.0.35 based machine.
>
> Does anyone have any suggestions?
>
> -- Nathan
We have a dual P-II 333, 256MB RAM, 24GB raid-5 array being served up by
1.9.18p10 (on Linux 2.0.33).  We typically have about 70 smbd processes
floating around.  When we first installed, performance was horrible, but
it wasn't the CPU (95% idle), Memory (usually 40MB buffered, swap is
hardly ever used), or Network (FTP ran at 1000k/s).  So, only samba was
left.  Reviewing my smb.conf I see a note that a DOS copy of the same
FTP test averaged 500k/s.  Setting socket options TCP_NODELAY,
IPTOS_LOWDELAY, read raw=no, and read prediction = yes got the download
speed to about 725k/s and the upload speed to 1100k/s (and the users off
my back!).

HTH
dave