As is the thing to do at 3am, i have been pondering the differences in IO performance be between the following setups, everything else being equal between the setups (for a VM store).
30x 3/4tb 3.5" 7200rpm capable of ~170MB/s (15x mirror vdev)
66x 1tb 2.5" 5400rpm capable of ~105MB/s (11x 6 disk z2 vdev)
Presumably the 66 drive would give better iops but how much (enough to justify the cost)? Would it be worth the cost difference over the 30 drive setup? (given a 36 drive supermicro case can be had much cheaper than a 72 drive 2.5" case)
As a side thing, should the vdevs be split differently for the setups?, ie, z2 vdevs instead of mirrors? ultimately there arent enough 1tb disks to break it into all mirrors and have the desired space so that would have to be z2 vdevs to give ~40tb usable, thats not the case for the 3/4tb disks. does the back end storage vdev configuration change drastically because of L2ARC and ZIL/SLOG additions? i see some people running a single z2/z3 for bulk storage behind the l2 and ZIL.
30x 3/4tb 3.5" 7200rpm capable of ~170MB/s (15x mirror vdev)
66x 1tb 2.5" 5400rpm capable of ~105MB/s (11x 6 disk z2 vdev)
Presumably the 66 drive would give better iops but how much (enough to justify the cost)? Would it be worth the cost difference over the 30 drive setup? (given a 36 drive supermicro case can be had much cheaper than a 72 drive 2.5" case)
As a side thing, should the vdevs be split differently for the setups?, ie, z2 vdevs instead of mirrors? ultimately there arent enough 1tb disks to break it into all mirrors and have the desired space so that would have to be z2 vdevs to give ~40tb usable, thats not the case for the 3/4tb disks. does the back end storage vdev configuration change drastically because of L2ARC and ZIL/SLOG additions? i see some people running a single z2/z3 for bulk storage behind the l2 and ZIL.