On Mon, Feb 1, 2010 at 4:10 PM, David Rees [off-list ref] wrote:

I suspect that if you used write-behind with a write-intent bitmap
stored only on the SSD, you'd get some of that performance back, but
potentially lose a bit of reliability.

You'd only lose data here if the SSD died and the machine crashed *at
the same time*, right?  Doesn't seem like a big deal to me -- if the
events are even a minute or two apart, you'd be fine (right?).  By
contrast, if I understand correctly, you can get data corruption in
RAID5 if you lose a disk and then the machine crashes *any* time
before a new disk is resynced.