Re: Deploying PostgreSQL on CentOS with SSD and Hardware RAID

On Sun, May 12, 2013 at 8:20 PM, John R Pierce <pierce(at)hogranch(dot)com> wrote:
> On 5/12/2013 6:13 PM, David Boreham wrote:
>>
>>
>> Not quite. More like : a) I don't know where to buy SLC drives in 2013
>> (all the drives for example for sale on newegg.com are MLC) and b) today's
>> MLC drives are quite good enough for me (and I'd venture to say any
>> database-related purpose).
>
>
> Newegg wouldn't know 'enterprise' if it bit them. they just sell mass
> market consumer stuff and gamer kit.
>
> the real SLC drives end up OEM branded in large SAN systems, such as sold by
> Netapp, EMC, and are made by companies like STEC that have zero presence in
> the 'whitebox' resale markets like Newegg.

The industry decided a while back that MLC was basically the way to go
in terms of cost and engineering trade-offs, at least in cases where
you needed a lot of storage. Yes, you can still get SLC in mid-tier
and up storage but:

*) a lot of these drives are simply re-branded intel etc
*) When it comes to SSD, I have zero confidence in vendor provided
hardware specs (lifetime, iops, etc). The lack of 3rd party test
coverage and performance benchmarking is a big problem for me. Ever
bought a SAN and have had it not do what it was supposed to?
*) The faster moving white box market has chosen MLC. Three years
back, the jury was still out. This suggests to me that SAN vendors
are still behind the curve in terms of SSD, which is typical of
enterprise storage vendors. But,
*) In many cases, the performance of the latest MLC drives is so fast
that many applications that would have needed to scale up to high end
storage would no longer need to do so. A software raid of say for
s3700 drives would probably outperform most <100k SANs from a couple
years back.

merlin