Re: squid + ftp = degraded performance?

From: Andreas Strotmann <>
Date: Fri, 21 Feb 1997 13:26:49 +0100


I think I've seen what you are referring to, too. However, only some
specific FTP servers appear to cause this particular problem during the
time that they are being tried.

The URL I consistently got this problem with this week is (timeout after 200 secs with an 'internal socket
error', code 500 in the log file), while (the same
data, the same machine) answers quickly. (For obvious reasons, I didn't
try more than twice...)

Other requests continue to be processed, though less quickly, including
FTP requests to servers not exhibiting this strange behaviour (i.e. most
FTP requests).

Every once in a while, another FTP request to another machine appears to
slow down Squid, too.

Wasn't there something about "PASV" FTP requests somewhere sometime?

My setup: Squid 1.1.5 on a SUN UltraSparc, Solaris 2.5.1

> > Normal response time through a monitoring script we have is around 0.2
> > seconds. However, it appears that the whole service slows down
> > (response times typically >50 seconds) when there are ftp requests
> > being made.
> >
> > Has anyone else seen this? (And if so, do you have a fix?)

Not that slow, but slow.
> Well, the same hapens with our proxy, and this only started after
> upgrading from squid 1.1.0 to 1.1.2. The current solution is to use a
> script testing the proxy every 5 minutes and if the response time is
> than 10 seconds it reinitializes squid (the average reponse time to the
> proxy is more or less the same as yours, i.e. 0.2 seconds). This is not
> much of a solution, but its better than not having a good reponse time
> (you cant imagine the quantity of people that complains if the proxy
> more than 10 seconds to reply).

The problem with this solution is that you may cut off other FTP transfers
of Netscape binaries, say, that users have been transmitting for a looong
time at that moment. You're lucky that they don't suspect why they have
to try again...

Perhaps you could run a second, older version squid on another port
dedicated for FTP requests, and parent all FTP requests to your main proxy
through that second proxy.


Andreas Strotmann       / ~~~~~~ \________________A.Strotmann@Uni-Koeln.DE
Universitaet zu Koeln  /| University of Cologne   \
Regionales Rechenzentrum| Regional Computer Center \
Robert-Koch-Str. 10    /|    Tel: +49-221-478-5524 |\   Home: -221-4200663
D-50931  Koeln        __|__  FAX: +49-221-478-5590 |__________~~~~~~~~~~~~   
Received on Fri Feb 21 1997 - 04:49:05 MST

This archive was generated by hypermail pre-2.1.9 : Tue Dec 09 2003 - 16:34:31 MST