On Thu, Jun 16, 2011 at 12:43 PM, Greg Smith <greg@2ndquadrant.com> wrote:
> There are already three layers involved here:
>
> -Database shared_buffers cache
> -Operating system read/write cache
> -RAID controller cache
>
> I would be skeptical that adding a fourth one near the bottom of this stack
> is likely to help a lot. And you're adding a whole new layer of difficult
> to test reliability issues, too. Overly complicated storage solutions tend
> to introduce complicated failures that corrupt your data in unexpected ways.
Plus each layer is from a different provider. The drive manufacturers
point to the RAID controller maker, the RAID controller people point
at the SSDs you're using, and so on...