We have a new FAS3040 with 3 shelves of 500GB SATA's. It has an onboard controller with 4 ports, and we have 2 expansion controllers with 2 ports each.
I'm trying to think about the aggregate layouts.
I am thinking that since these are SATA drives, I should put all 3 shelves into 1 big aggregate for performance (to get as many spindles as possible) and then just use flex vols.
But then I also am thinking that if I use 3 separate aggregates (1 per shelf), I would have better data protection in case I loose a whole shelf (only loose volumes on that one shelf). Since the raid_size is maxed at 16 for SATA anyways, I am going to end up with a raid group per shelf no matter what (defaults to 14).
I've done some write tests. I had an aggregate made from 1 shelf and another aggregate made up of 2 shelves. I didn't see much difference. I was write testing via NFS mounts. The client was on a GigE, and the filer was on a VIF made up of all 4 GigE ports.
Is the performance gains from having mutli-shelf aggregates worth the loss of the data protection from a whole shelf failure.
As for the FC connections, currently I have all 3 shelves daisy chained with 2 loops, one loop is on the on board and the other loop is on one of the expansion cards.
Suggestions ?
Thanks !
Paul