"Jeff" == Jeff Moyer <jmoyer@redhat.com> writes:
Jeff> Chuck Anderson <cra@WPI.EDU> writes:
On Mon, Mar 01, 2010 at 04:46:44PM -0500, Jim Dibb wrote:
On Mon, Mar 1, 2010 at 4:21 PM, Chuck Anderson <cra@wpi.edu> wrote:
I'm interested. I was considering using SSDs for my boot drive. Is RAID protection necessary/advisable using SSDs?
SSDs have much higher reliability than HDD. Mirroring is the only RAID level that does not impose a write penalty. Mirroring SSDs is expensive
Based on these 3 points, I'd say a backup is a much better solution than RAID, unless you want to (R)AID-0 them into a stripe for even more insane performance.
But then again, you didn't state how important your uptime of your system is. Sorry for leaving that bit out....
Uptime/availability isn't that important, but backups are since RAID *is* my backup (plus rsync to other RAIDed systems for the most important data). With traditional disk drives, it hasn't been too expensive to slap a 2nd system drive in for RAID 1/mirroring. SSDs are much more expensive, so if as you say they are more reliable, perhaps I can forgo the expense of doing RAID on them.
Jeff> I've seen many claims that SSDs are more reliable than Jeff> traditional HDDs, but I haven't seen data to back up those Jeff> claims. Some of the arguements I've read on SSD reliability are quite interesting. If you do the math on how much data you need to write to destroy an SSD with proper (note!) wear levelling, it's really quite high. But I think the real key is to write data to them in blocks of 512 bytes as much as possible, and to not write smaller amounts if at all possible. Jeff> My main concern is that SSDs are still young, so they haven't Jeff> had much soak time. Whether or not the flash is reliable is Jeff> only a small part of the battle. Buggy firmware is a much more Jeff> likely problem at this stage in the game. No single point of Jeff> failure is a good design point when dealing with your data. ;-) I think this is a key issue, the firmware and controllers, not the flash chips themselves. Jeff> I remain cautiously optimistic (though I've already bricked one Jeff> drive). Details? John