Performance tips for heavily loaded servers

[Kalle Kiviaho]

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 at ios.chalmers.se