RE: [squid-users] Problem with RAM usage with squid

Hi ,

The typical output of free in our system is given below. Free RAM
gradually decreases and we are left with no option but to reboot the
system (once in 5-6 hours).

What is surprising is that used swap figure is always zero (as seen in
free output below) . Is it expected ? I would think that swap should be
used if RAM is full.

I donot suspect memory leaks causing the issue, as top command would
show ipchains or squid or any other program using that memory if that is
the case.

             total used free shared buffers
cached
Mem: 513348 465460 47888 0 24076
304704
-/+ buffers/cache: 136680 376668
Swap: 1052216 0 1052216

Thanks,
Tushar

-----Original Message-----
From: Henrik Nordstrom [mailto:hno@squid-cache.org]
Sent: Monday, March 31, 2003 11:50 PM
To: Tushar Gupta
Cc: squid-users@squid-cache.org
Subject: RE: [squid-users] Problem with RAM usage with squid

Also, if you are using Linux-2.4, then make sure to use iptables and not
ipchains for the interception. ipchains REDIRECT is broken in many
Linux-2.4 versions, causing a kernel memory leak which will eventually
make your machine completely halt due to lack of memory..

Regards
Henrik

mån 2003-03-31 klockan 19.38 skrev Henrik Nordstrom:
> Please try to answer the questions below.
>
> Regards
> Henrik
>
> mån 2003-03-31 klockan 17.25 skrev Tushar Gupta:
> > Hi,
> >
> > The problem of RAM in our configuration remains unsolved. Another
thing
> > we noticed is that swap used as seen by free command always remains
> > zero. Does it give any clue on what may be the problem.
> >
> > We use squid in httpd accelerator mode (interception)
> >
> > Thanks for any suggestions
> >
> > Tushar
> >
> > -----Original Message-----
> > From: Henrik Nordstrom [mailto:hno@squid-cache.org]
> > Sent: Friday, February 21, 2003 1:35 AM
> > To: Tushar Gupta; squid-users@squid-cache.org
> > Subject: Re: [squid-users] Problem with RAM usage with squid
> >
> > Why would you want to do such a thing?
> >
> > The "buffer/cache" is automatically returned if applications need
more
> > memory.
> >
> > Your problem is elsewhere. You say the idle CPU goes to zero. Which
> > application is usin all your CPU? (see top).
> >
> > And how much memory is reported by free in the "+/- buffers/cache"
> > row?
> >
> > Regards
> > Henrik
> >
> > On Thursday 20 February 2003 15.54, Tushar Gupta wrote:
> > > Hi,
> > >
> > > Is there any mechanism by which I can flush or free up RAM without
> > > need to reboot the server
> > >
> > > Tushar
> > >
> > >
> > > -----Original Message-----
> > > From: Henrik Nordstrom [mailto:hno@squid-cache.org]
> > > Sent: Tuesday, January 28, 2003 2:53 PM
> > > To: Tushar Gupta; squid-users@squid-cache.org
> > > Subject: Re: [squid-users] Problem with RAM usage with squid
> > >
> > > The free ram as reported by top should only be a few MB when a
> > > server has been in use for a while. What is not used by
> > > applications should be used by bufffer/cache.
> > >
> > > See the output of free for a better reading of "free" ram.
> > >
> > > What to watch is the swap usage. On a Squid server the swap usage
> > > should be low and not increasing.
> > >
> > >
> > > This said, there has been a number of memory leaks in early
> > > Linux-2.4 kernels. Upgrading to a current 2.4 kernel is most
likely
> > > recommended.
> > >
> > > The most commonly hit issue by Squid useds it that the ipchains
> > > REDIRECT target was utterly broken up to 2.4.18 something. Use the
> > > native Linux-2.4 iptables command instead.
> > >
> > > Regards
> > > Henrik
> > >
> > > On Tuesday 28 January 2003 08.18, Tushar Gupta wrote:
> > > > Hi,
> > > >
> > > > We are using squid for caching, with SCSI disk and 512 MB RAM.
> > > > The cache_mem setting in squid.conf is 64 MB. After running for
> > > > several hours total free RAM (as seen by top command) reduces to
> > > > few kilobytes and server response time increases (CPU idle
cycles
> > > > also go to zero), and we need to reboot the server. Though as
> > > > percentage of total CPU usage squid is usually taking around
> > > > 15-30%CPU and percentage of RAM as 12-15%MEM . After rebooting
> > > > the server would again run fine for several hours say half a
day,
> > > > and then RAM would gradually get consumed again.
> > > >
> > > > It is Linux 7.1 , Kernel 2.4.2-2 on i686 (PII 350 Mhz), squid
> > > > version 2.3.stable4. Server also has other services like
> > > > DNS/qmail but they take negligible CPU/RAM
> > > >
> > > > Any suggestions are welcome.
> > > >
> > > > Thanks
> > > > Tushar

-- 
Henrik Nordstrom <hno@squid-cache.org>
MARA Systems AB, Sweden