Re: Optimal settings for RAID controller - optimized for writes

On Tue, Feb 18, 2014 at 2:41 PM, Tomas Vondra <tv(at)fuzzy(dot)cz> wrote:
> On 18.2.2014 02:23, KONDO Mitsumasa wrote:
>> Hi,
>>
>> I don't have PERC H710 raid controller, but I think he would like to
>> know raid striping/chunk size or read/write cache ratio in
>> writeback-cache setting is the best. I'd like to know it, too:)
>
> We do have dozens of H710 controllers, but not with SSDs. I've been
> unable to find reliable answers how it handles TRIM, and how that works
> with wearout reporting (using SMART).

AFAIK (I haven't looked for a few months), they don't support TRIM.
The only hardware RAID vendor that has even basic TRIM support Intel
and that's no accident; I have a theory that enterprise storage
vendors are deliberately holding back SSD: SSD (at least, the newer,
better ones) destroy the business model for "enterprise storage
equipment" in a large percentage of applications. A 2u server with,
say, 10 s3700 drives gives *far* superior performance to most SANs
that cost under 100k$. For about 1/10th of the price.

If you have a server that is i/o constrained as opposed to storage
constrained (AKA: a database) hard drives make zero economic sense.
If your vendor is jerking you around by charging large multiples of
market rates for storage and/or disallowing drives that actually
perform well in their storage gear, choose a new vendor. And consider
using software raid.

merlin