[Samba] excessive TCP retransmissions with samba 3.0, slow file opening

[Jeremy Anderson]

Thanks for the quick response, Paul!

On Thu, May 12, 2005 at 07:38:47AM -0500, Paul Gienger wrote:
> 
> Hubs? HUBS? I hope you meant switches. If not, go buy some switches.

10/100 hubs.  This is a small client, with limited hardware budget.
So, it's a pair of 8-port 10/100 hubs, connected.

> >I want to suspect hardware, but flood pings from a linux box put on the 
> >network never report dropped packets.  
> >
> Then go back to hardware.  Unless you've got firewalls or something in
> the mix that's probably where your traffic is going.  Watch the
> collision lights on your hubs and see if they go nuts when the problem
> occurs.

Hrm.  Good point.  Wish I'd thought of that.  I've found a new caveat, however.
One of the machines in the office is absolutely unaffected by the problem.  It opens extremely large files very quickly.

I find that one user has been reporting the problem for several weeks, and now three more users have begun experiencing
it in the past week.

I cannot find any differences between the fast machine and the "slow" machines--except the fast machine has slightly older hardware than the slow machines.  All are running Windows 2000 SP4.

And, when I connected from my linux laptop using smbclient, transfers are instantaneous (or close enough)

I'm beginning to suspect this is a client issue.  The problem, however, remains, and the client would be happiest if I could make things fast again.

> SMB is pretty chatty as far as protocols go.

Yes, it is, but I did some big scp transfers, and would have expected to see at least SOME TCP retransmits if it's a hardware issue.  Also, SMTP, POP3, and IMAP are very, very fast on the network--no delays whatsoever, while SMB traffic is not.

I'd like to believe that a hardware problem would affect all protocols equally--but I'm not so sure about that supposition.

The hubs were hot to the touch, I wonder if they're starting to fail.  One of them is circa-1997--I know that's when I got the exact same piece of hardware as a promo from 3COM (an officeconnect hub).

Jeremy
-- 
Jeremy Anderson		jeremy (at) angelar.com	
http://www.angelar.com/~jeremy