[squid-users] Squid high bandwidth IO issue (ramdisk SSD)

Dear ALL,
We have a squid server with high volume of traffic, 200 – 300 MB.
The server is in transparent mode and using 18GB of ramdisk. With this
configuration performance is very good (after optimizing the squid and the
linux machine).
The problem is the small size of cache directory.
Since IO is a big issue with squid we purchased the intel ssd x25-m 160gb
with hope that a flash drive will overcome the IO problems.
Unfortunately we failed. After adding the SSD disk and configuring squid to
use another cache directory we encountered high IO that led to performance
degradation.

We have tried using AUFS and even downgrading to version 2.6 and using COSS
with no success.
Does any one have an idea how to overcome the IO problems?
Do you have a suggestion to configuring squid in a big enterprise with big
traffic volume?

We have searched the WEB and used as reference links such as:
http://www.freeproxies.org/blog/2007/10/03/squid-cache-disk-io-performance-enhancements/
http://blog.last.fm/2007/08/30/squid-optimization-guide

Platform: x3455 – 2 x dual core opteron 2.5Ghz
OS Memory: 32GB (24GB to ramdisk)
OS: Linux RHEL 5.0

Squid configuration:

acl manager proto cache_object
acl localhost src 127.0.0.1/32
acl to_localhost dst 127.0.0.0/8
acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
acl ib src XXXXXXXXXXXXXX
acl mgt src XXXXXXXXXXXXX
acl SSL_ports port 443
acl Safe_ports port 80 # http
acl Safe_ports port 21 # ftp
acl Safe_ports port 443 # https
acl Safe_ports port 70 # gopher
acl Safe_ports port 210 # wais
acl Safe_ports port 1025-65535 # unregistered ports
acl Safe_ports port 280 # http-mgmt
acl Safe_ports port 488 # gss-http
acl Safe_ports port 591 # filemaker
acl Safe_ports port 777 # multiling http
acl CONNECT method CONNECT
http_access allow manager localhost
http_access deny manager
http_access deny !Safe_ports
http_access deny CONNECT !SSL_ports
http_access allow ib
icp_access allow localnet
icp_access deny all
htcp_access allow localnet
htcp_access allow all
http_port 3128 transparent
hierarchy_stoplist cgi-bin ?
cache_mem 100 MB
maximum_object_size_in_memory 34 KB
cache_replacement_policy heap LFUDA
cache_dir ufs /tmp/ramdiskt 18000 16 256
maximum_object_size 8 MB
cache_swap_low 90
cache_swap_high 95
access_log none
cache_store_log none
refresh_pattern ^ftp: 1440 20% 10080
refresh_pattern ^gopher: 1440 0% 1440
refresh_pattern (cgi-bin|\?) 0 0% 0
refresh_pattern . 0 20% 4320
half_closed_clients off
shutdown_lifetime 10 seconds
snmp_access allow ibsnmp mgt
snmp_access allow ibsnmp
snmp_access deny all
snmp_incoming_address 0.0.0.0
snmp_outgoing_address 255.255.255.255
icp_port 0
log_icp_queries off
dns_nameservers XXXXXXXX
hosts_file /etc/hosts
client_db off
coredump_dir /var/spool/squid
pipeline_prefetch on

Regards.

-- 
View this message in context: http://www.nabble.com/Squid-high-bandwidth-IO-issue-%28ramdisk-SSD%29-tp24775448p24775448.html
Sent from the Squid - Users mailing list archive at Nabble.com.