thanks for the replies, guys. yes, we're using squid in a farm with very high performance requirement, as it's doing http acceleration for our origin servers. we're replacing 2disk SATA with 6disk SCSI, and while I gather there are diminishing returns with adding over 3 or 4 spindles, having a decent cache size is probably second in importance. we'll be going from 2 cache_dirs of 10Gb each to 6 cache_dirs (one on each disk) with 5Gb each. our cache_mem size is 2048mb, which puts us just over the 10mb/1Gb mem-to-disk suggestions, but the boxes have 4Gb of RAM in them, and we can add more if need be. we're doing roughly 3000 req/sec across an 8 machine farm, and these SATA drives are getting awfully hot, with over an 80% hit rate (40% mem, 40% disk). the objects never change once they are in cache except for small cases, in which case we make an explicit PURGE. we see upwards of 80-100% disk utilization at peak, so getting the faster/more disks (ext2 with noatime, btw) seemed like a good idea. :) ok, from what you're both saying, I might not have to worry about where to put the 5Gb partitions on these drives, but basically, it can't hurt. I've been going on the assumption that the most important performance gains will come from 1) the xtra spindles, and 2) the better seek times on the 15K SCSI (versus 7200k SATA) drives. thanks, john
