Memory Usage etc.

From: Fredo Sartori <>
Date: Tue, 14 Jan 1997 23:39:22 +0100

Hello Squiders,

we are running squid-1.1.3 on a SGI Challenge L (2 CPUs, MIPS R4400,
768MB). Squid is configured to use 300MB memory and about 20GB disc
space for caching. We are handling 1.5 requests per second on average
and about 3 to 4 requests per second during peak times.

After running squid for two months we found some strange behavior
of the program:

1. Memory Usage:
The Memory squid is using tends to grow steadily. Typically during the
first 6 hours the process size (resident size) increases at a rate of
45MB/h. In a second stage (24 hours) the grow rate is about 5MB/h till
a process size of approx. 410MB is reached. From then on squid grows by
.5MB/h for the remaining time (90h) we monitored this process.
Because of this ever increasing memory usage, we are forced to restart
squid every 5 to 7 days!

What can we do to stop squid from growing? We already use gnumalloc.
Btw is there an explanation for this 3 stage growing process?

2. Disc Usage:
We have 20GB of disc cache but squid only uses about 12GB. Given high
low water marks of 98% and 90% we expect a disc usage of 18 to
19.5GB. We would have enough traffic through our proxy server to
fill the entire disc cache in 3 to 4 days!

What prevents squid from using the whole disc cache?

3. Disc Utilization:
We found in some cases that squid does not use objects stored in the
disc cache but instead requests them from neighbors (though the own
objects are "fresh"). This behavior forces up the response
times of our server massively!

Any hints are welcome!


Some parameters from our squid.conf:
cache_mem 300
cache_mem_low 75
cache_mem_high 90

cache_swap 19000
cache_swap_low 90
cache_swap_high 98

maximum_object_size 10240

memory_pools off

swap_level1_dirs 256
swap_level2_dirs 256
store_avg_object_size 20

Fredo Sartori                       ! Freie Universitaet Berlin
Phone:  (030) 838-5903              ! ZEDAT
Fax:    (030) 838-6721              ! Fabeckstr. 32
E-mail:       ! D-14195 Berlin, FRG
Received on Tue Jan 14 1997 - 14:58:29 MST

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