Squid / OS interaction

Memory usage
Lots
Lots
Lots

Object index is kept in-memory
Object data is kept in-memory, but is freed to try and meet cache_mem limits
Partial object data can be kept in-memory (unlike squid-1-vm)
Must make certain process/user limits are set very high
Do not ever allow swapping, ever
Try not to run much else on a busy squid box
Turn off priority_paging under Solaris 7
Turn on vm.defer_swapspace_pageouts under FreeBSD