Very slow performance after installing RAID controllers

Bill Moran wmoran at
Thu Oct 25 06:26:06 GMT 2001

On Thursday 25 October 2001 02:40, Thomas Cameron wrote:
> I just installed two Smart-2/P array controllers and an additional F1
> external array, this one with 36GB drives.  This puts one external array on
> each of the array controllers.  I also upgraded to Red Hat 7.1.  Now,
> network performance is horrible!  a 100 meg file takes 15-20 minutes to
> copy from the server to a client PC.

I think you're posting to the wrong list ... you changed HW and OS and
you blame samba for network problems?

> Here's the weird part - when I copy files from one external array to the
> other using the cp command at the console, it is very fast (650MB in under
> two minutes).  When I copy files within each array, it is also similarly
> fast.  So, I don't think it is disk subsystem - I only mention it because
> I'm grasping at straws here.

Yes, but if you FTP/scp or do any other kind of _network_ copying (other
than through samba) how does the performance look?  If it looks as crappy
as the samba performance, then you need to look at your network config
before bothering with samba.

> I have tried downloading and compiling Samba 2.2.2.  I have fiddled with
> SO_SNDBUF and SO_RCVBUF as well, but it doesn't affect the speed at all.

You may be tweaking the wrong knobs.

> Anyone have any idea why network performance would tank so badly in these
> circumstances?  I really don't want to yank the array controllers, but I'm
> about at the end of my rope...

New hardware that conflicts with your network card?  New OS that with buggy
drivers for your network card?  I think these would be more likely suspects at
this point than samba.
Do some transfer tests with ftp and/or scp or any other network traffic (other
than samba) and see if the performance is up to what you expect.  If it doesn't
match the crappy samba performance, then you may have a samba problem.
But all network traffic is slow, you'll want to check interrupts, ifconfig and even

Bill Moran
Potential Technology technical services
(412) 793-4257

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