Exchange and SSDs

I'm designing an Exchange 2010 system at the moment as an upgrade from a clustered Exchange 2003 environment.

I won't go in to the details about the restrictions in the current system, save to say that even after having lots of physical spindles thrown at it, it's still IO bound.

So the new system is going to have SSD. And what a lot of fun that's turning out to be. Try finding some hard data on the life expectency of MLC SSDs under genuine enterprise (i.e. not desktop) workloads. Go on, I dare you. I'd settle for real-world life expectencies of MLC drives full stop.

Instead, everyone's throwing around the 10,000 program/erase cycle design spec with a caution to keep an eye on it, and the vendors seem reluctant to let go any real information how many writes you can expect to get away with before hard errors start to crop up.

Use SLC you say? Fair enough, but until the cost per GB comes down it's still likely to be more cost effective to burn through a couple of same-size MLCs on a price per GB per year equation. I think. See above re: vagaries of predicting drive failure.

Either SSD is still finding its feet in the enterprise space, or people just aren't writing about it yet. Or maybe the drives just haven't started to fail.

Reliability will improve as the technology continues to mature, and it's maturing fast. Even if I only get 6 months before the first drives start to burn out, which I think is exceedingly pessimistic, the replacement drives are likely to be hardier, and cheaper even then.

Anyway, I'm looking forward to getting of the design sheet on this one and starting to push bytes around. Stay tuned.