Re: Can't figure out why Squid Swaps => Performance drops

It is quite normal for Linux (which I assume you are using) to start using
swap in favor of allocating memory for buffers and cache. What you'll
find is that squid is swapping, but that other unused processes are
getting swapped out to disk. For instance, on my system, mingetty is
often swapped out after a while, here's the snippet from ps aux:

root 763 0.0 0.0 1076 0 tty2 SW Mar01 0:00 [mingetty]
root 764 0.0 0.0 1076 0 tty3 SW Mar01 0:00 [mingetty]

To determine if squid itself is hitting swap, you need to look at the
cachemgr output, under "General Runtime Information" you'll see "Page
faults with physical i/o" which is when squid is swapping. Hopefully,
that number is low, otherwise you may want to decrease the amount of
memory you've allocated to squid. From you system stats, things look good
if squid is the only thing running.

-Dave

On Mon, Mar 06, 2000 at 12:02:14PM +0100, Plak, Peter wrote:
>
> I can't figure out why my system swaps between 4 and 7 Mbytes. The FAQ says
> that Squid's performance degrades significant if Squid goes swapping ! I
> gave Squid 64 Mb cache_mem.
>
> I have Squid 2.2 Stable 5 and 192 MB RAM, 400 MHz PII. My cache is currently
> 1.5 Gbyte. Below you see the output op "free" en "top". There are currently
> no big processes active, only Squid.
>
> total used free shared buffers cached
> Mem: 193232 190184 3048 8868 22656 16772
> -/+ buffers/cache: 150756 42476
> Swap: 136512 4504 132008
>
> 11:45am up 6 days, 12:33, 1 user, load average: 0.00, 0.00, 0.00
> 30 processes: 29 sleeping, 1 running, 0 zombie, 0 stopped
> CPU states: 0.5% user, 0.5% system, 0.0% nice, 98.8% idle
> Mem: 193232K av, 190120K used, 3112K free, 9336K shrd, 22624K buff
> Swap: 136512K av, 4484K used, 132028K free 16456K cached
>
> PID USER PRI NI SIZE RSS SHARE STAT LIB %CPU %MEM TIME COMMAND
> 1552 nobody 13 0 134M 132M 1932 S 0 0.5 70.3 19:57 squid
>
> Can someone tell me if I should change some portions of buffers, cache_mem
> or something else, please.
>
> Greets Peter from Holland
>
Received on Mon Mar 06 2000 - 13:07:58 MST