It is expected that our storage will consist of a combination of fast fibre channel and SATA based disk and we would like to implement a system whereby
why do you think that's a good design? consider bandwidth: you will spend
5x as much on FC, but can easily obtain the same or higher bandwidth with
SATA given that it's so much cheaper. (not to mention the fact that bandwidth is rpm * recording density, and SATA is consistently a generation or two ahead in density. that means that a 10k rpm FC disk may sustain 120 MB/s, but a 7200 rpm SATA will do 130 over the same size (and slow down to 90 or so on inner tracks - that is, at 3x the capacity of the FC disk...)) IMO, you'd do better to provide seeky workloads with their own filesystems, and put everyone else on plain old SATA (made to scale to arbitrary bandwidth and concurrency goals with, eg Lustre). that way someone dumping a 5TB checkpoint won't trash performance for people doing metadata or seek-intensive stuff. and as a side-benefit, the costliness of md/seek stuff becomes visible to those doing it... _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
