This page describes the configuration details for the Squid entry at the Second IRCache Bakeoff.

Hardware

• Asus P2B-D dual processor motherboard
• Dual Pentium III/450MHz CPU's
• 512 MB RAM
• Western Digital 6.0GB IDE disk
• Six IBM DDRS-39130W 8.5GB SCSI disks
• Adaptec 2940-UW PCI SCSI controller
• Intel Etherexpress Pro/100+ NIC
• 3COM TP-800 fast ethernet hub

Total hardware cost: US$ 4320

Software

• FreeBSD 3.3-RELEASE
• Squid-2.4.DEVEL2

FreeBSD kernel

We used a customized FreeBSD kernel. Of particular note:

• Symmetric Multi-Processing support is enabled.
• All unused or unneeded drivers and devices are removed.
• SCSI_DELAY is set to 500 milliseconds so the system boots quicker.
• NMBCLUSTERS is set to 32k, just in case.
• Shared Memory and Message Queue parameters are tweaked.
• AHC_ALLOW_MEMIO is defined to enable memory mapped I/O with the SCSI controller.

Here's the dmesg output if you're interested.

Other system tuning

Certain services such as cron, inetd, and sendmail are disabled in /etc/rc.conf.

In /etc/rc.local, we use sysctl to change settings for somaxconn, delayed acks, and the ephemeral TCP port range.

Disks and Filesystems

Each of the six IBM disks are formatted as a single UFS filesystem with the default parameters. Filesystems are mounted with the noatime option.

Squid configuration

Our squid.conf is very basic:

• Disk I/O is done with the external DISKD processes.
• access controls are minimal; all requests are allowed.
• ICP is diabled by setting icp_port to zero.
• each cache_dir is given 4 GB of disk space.
• The access log and store log are disabled.
• 128 MB is used for the hot object memory cache.

Results

These results are taken from the Official IRCache Second Bake-Off Report. Please take the time to compare Squid's results with the other participants. Especially the response time and hit ratio traces, and the performance/price comparisons.

Summary
Throughput:	160.30 rep/sec
Mean Response time:	1.412 sec
Mean Miss Response Time:	2.844 sec
Mean Hit Response Time:	0.241 sec
Hit Ratio:	54.99 %
Errors:	0.00 %

Note that Squid demonstrates the second best overall response time, and the highest hit ratio.

Throughput Trace

Response Time Trace

Hit Ratio Trace

Logs

For what its worth, here's the Squid cache.log from the two test runs, and some df output taken to show how full the disks got.