> From: [email protected] [mailto:discuss- > [email protected]] On Behalf Of Skylar Thompson > > It really depends - while 24 10K disks will give you more concurrency > and throughput, it won't be able to beat the single-operation latency of > 15K disks.
Basically, if you're going to benchmark a single operation, it doesn't matter what kind of disks you have, or how the raid is configured. A single disk = a mirror = raid5 =raid6 = raid10. (The only choice that will matter is SSD vs HDD.) But even if you have a bunch of random IO operations that are all independent of each other, they are NOT each an instance of a single operation. Drives and controllers have a lot of intelligence built into them, to optimize disk performance over a large pool of requested operations. If you give it 20 random seeks concurrently, it will reorder those seeks using an elevator algorithm (or whatever algorithm it determines to be best) so the results will be returned not necessarily in the same order they were requested, but in the minimum possible time. I can't really think of a situation where you would care about the performance of a single operation. Meaning, if you *consistently* issue a single operation, and then wait for it to complete before you issue any more operations of any kind. _______________________________________________ Discuss mailing list [email protected] https://lists.lopsa.org/cgi-bin/mailman/listinfo/discuss This list provided by the League of Professional System Administrators http://lopsa.org/
