Spec'ing out a few new servers and in talking to my rep, he brought up a good point:
"Mirroring an SSD doesn’t make a lot of sense. The die from the number of writes and if you are going to write the exact same thing to both drives they should fail at the exact same time 2,000,000 hours later, 120 years.
We sell about 15,000 enterprise SSDs a quarter and we don’t do more than a handful of RMAs on them a year from malfunction."
While I can't find much fault in his logic, I still feel... "weird" not running a server with RAID1/RAID10 drives (I've always done RAID10 HDDs, so this foray into SSDs on server is new for me...)
Thoughts?
Funny. I just finished my project of replacing my old WHS-2011 server with a 2012 R2 Essentials and Ivy Bridge with PCIE 3.0 hardware. I was kicking back flipping my DVR library on the new box, and I was thinking the same thing. I had some lucid thoughts about it.
SSDs are still too expensive for that sort of thing. I don't do RAID anymore, nor any RAID1 or flavors of it. I can have three-disk file and folder duplication in my drive pool. And I could do that with SSDs.
But how much would you spend on a 1TB SSD? $300? $400? I bought a 2TB Crucial MX300 last year for something like $550.
My old WHS-11 drive pool is made of 2TB Seagate NAS disks -- four of them. I can re-deploy those drives, but now the bigger ones are less than what I paid for the Seagates. And -- I'm modest: I only chose 3TB disks for the new box, while I can re-deploy the 2TB units as backup drives.
Think about it. If you wanted 8TB of SSD drive pool, you could spend between $1,600 and $2,000 on -- say -- four 2TB Crucials. On the up side, your server would be sucking less power from the wall -- a saving for 24/7 operation. But the electro-mechanical HDDs are greater in capacity, and they cost a fraction of an SSD. I just bought two 3TB Hitachi Enterprise drives on sale for $50 each. I have a third one, so together that's 9TB for maybe $200. Instead of the four drives I had in the old server, I now only run three.
No -- here's what I do, and I think it happened to coincide with an opinion by Terry Walsh in his server-OS books. Use an SSD for the server OS itself; use hard disks for the drive pool -- connected to a $100 SuperMicro [Marvell] PCIE x8 controller. I'm even testing the trial version of PrimoCache Server, given that I have 16GB of DDR3-1600. I should've finished this project 2 years ago!
Your power savings are not going to cover the cost of those SSDs anytime in a medium to short-range time-horizon. Your power savings can still benefit by using larger but fewer HDDs. You can do your RAID 1, RAID 1/0, RAID 5 or 6 with more expensive hardware if you want the latter two and a hardware RAID controller. But I get file/folder duplication (x3 "triplication" if I want!). Don't need to mirror whole drives to do it.
Ultimately, it's true -- the SSDs are not going to pose a risk like the HDDs. But they're going to cost a lot more. Well -- maybe you were thinking about an OS-boot-system drive for a server using mirrored SSDs. But why not just back up a 250GB OS partition to a 1TB HDD once a day? And of course -- a mirrored array is only redundant -- it isn't "backup."