On 06/20/2011 11:54 PM, Dan Harris wrote:
I understand that the majority of consumer grade SSD drives lack the required capacitor to complete a write on a sudden power loss. But, what about pairing up with a hardware controller with BBU write cache? Can the write cache be disabled at the drive and result in a safe setup?
Sometimes, but not always, and you'll be playing a risky and unpredictable game to try it. See http://wiki.postgresql.org/wiki/Reliable_Writes for some anecdotes. And even if the reliability works out, you'll kill the expected longevity and performance of the drive.
I'm exploring the combination of an Areca 1880ix-12 controller with 6x OCZ Vertex 3 V3LT-25SAT3 2.5" 240GB SATA III drives in RAID-10. Has anyone tried this combination? What nasty surprise am I overlooking here?
You can expect database corruption the first time something unexpected interrupts the power to the server. That's nasty, but it's not surprising--that's well documented as what happens when you run PostreSQL on hardware with this feature set. You have to get a Vertex 3 Pro to get one of the reliable 3rd gen designs from them with a supercap. (I don't think those are even out yet though) We've had reports here of the earlier Vertex 2 Pro being fully stress tested and working out well. I wouldn't even bother with a regular Vertex 3, because I don't see any reason to believe it could be reliable for database use, just like the Vertex 2 failed to work in that role.
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