[squid-users] access to cache is very high

guys,

I've been using squid for 5 years in my educational institution
(IM Telkom - Telkom Institute of Management)
but this is the first time i encounter this problem.
need your expertise.

I'm using HP Proliant ML110 G5 with 320GB of SATA disk.

I'm using squid 2.6 stable 16 (FreeBSD 6.3) with 100GB of squid-cache.
when the cache was not yet full, there's no problem whatsoever
but when the cache is full (but still 90% of the mountpoint),
squid is always busy validating its objects
and refusing all client connection.

this is part of file /usr/local/etc/squid/squid.conf
------------------------------------------------
maximum_object_size 16384 KB
minimum_object_size 0 KB
maximum_object_size_in_memory 8 KB
cache_replacement_policy lru
memory_replacement_policy lru
cache_dir ufs /webcache 100000 64 256

this is the capture when the squid refusing connection
-------------- (using top) ----------------------------------
CPU states: 39.5% user, 0.0% nice, 55.3% system, 5.3% interrupt, 0.0% idle
  PID USERNAME THR PRI NICE SIZE RES STATE TIME WCPU COMMAND
77059 squid 1 123 0 186M 184M RUN 0:10 86.26% squid

-------------- (using systat) ----------------------------------
      /0% /10 /20 /30 /40 /50 /60 /70
ad4 MB/sXXXXX
   tps|XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

-------------- (cache.log) ----------------------------------
2009/03/20 09:54:44| httpAccept: FD 11: accept failure: (53) Software caused connection abort

      
Received on Sat Mar 21 2009 - 00:16:15 MDT