Re: SSDs with Postgresql?

On Thu, April 14, 2011 10:51, Craig Ringer wrote:
> On 14/04/2011 4:35 PM, Henry C. wrote:
>
>
>> There is no going back.  Hint: don't use cheap SSDs - cough up and use
>> Intel.
>>
>
> The server-grade SLC stuff with a supercap, I hope, not the scary
> consumer-oriented MLC "pray you weren't writing anything during power-loss"
> devices?

That's what a UPS and genset are for.  Who writes critical stuff to *any*
drive without power backup?

You have a valid point about using SLC if that's what you need though. 
However, MLC works just fine provided you stick them into RAID1.  In fact, we
use a bunch of them in RAID0 on top of RAID1.

In our environment (clusters) it's all about using cheap consumer-grade
commodity hardware with lots of redundancy to cater for the inevitable
failures.  The trade-off is huge:  performance with low cost.

We've been using MLC intel drives since they came out and have never had a
failure.  Other SSDs we've tried have failed, and so have hard drives.  The
point though, is that there are tremendous performance gains to be had with
commodity h/w if you factor in failure rates and make *sure* you have
redundancy.

h