Squid / OS interaction

Filesystem - ReiserFS

Newish Linux filesystem
Modern IO clustering
Modern (non-linear) directory indexing
Better throughput than ext2 or ffs
But not by leaps and bounds
Should mount with notails, so the FS doesn't try to "pack" file fragments
Has has stability issues in the past with certain configurations
At least one squid vendor (http://www.swelltech.com/) uses ReiserFS on their shipped servers