If you can cite a specific device that draws more than 10% of the equivalently performing (e.g., short stroked) array,
Iwould be very interested. There may be a DRAM SSD that draws more than a flash SSD, but I'd be really surprised to
finda flash SSD that draws the same as any HDD, even at gross capacity.
Robert
---- Original message ----
>Date: Tue, 17 Aug 2010 23:37:26 -0700 (PDT)
>From: pgsql-performance-owner@postgresql.org (on behalf of david@lang.hm)
>Subject: Re: [PERFORM] Completely un-tuned Postgresql benchmark results: SSD vs desktop HDD
>To: Brad Nicholson <bnichols@ca.afilias.info>
>Cc: pgsql-performance@postgresql.org
>
>On Thu, 12 Aug 2010, Brad Nicholson wrote:
>
>> On 10-08-12 03:22 AM, Arjen van der Meijden wrote:
>>> On 12-8-2010 2:53 gnuoytr@rcn.com wrote:
>>>> - The value of SSD in the database world is not as A Faster HDD(tm).
>>>> Never was, despite the naive' who assert otherwise. The value of SSD
>>>> is to enable BCNF datastores. Period. If you're not going to do
>>>> that, don't bother. Silicon storage will never reach equivalent
>>>> volumetric density, ever. SSD will never be useful in the byte bloat
>>>> world of xml and other flat file datastores (resident in databases or
>>>> not). Industrial strength SSD will always be more expensive/GB, and
>>>> likely by a lot. (Re)factoring to high normalization strips out an
>>>> order of magnitude of byte bloat, increases native data integrity by
>>>> as much, reduces much of the redundant code, and puts the ACID where
>>>> it belongs. All good things, but not effortless.
>>>
>>> It is actually quite common to under-utilize (short stroke) hard drives in
>>> the enterprise world. Simply because 'they' need more IOps per amount of
>>> data than a completely utilized disk can offer.
>>> As such the expense/GB can be much higher than simply dividing the capacity
>>> by its price (and if you're looking at fiber channel disks, that price is
>>> quite high already). And than it is relatively easy to find enterprise
>>> SSD's with better pricing for the whole system as soon as the IOps are more
>>> important than the capacity.
>>
>> And when you compare the ongoing operational costs of rack space, powering
>> and cooling for big arrays full of spinning disks to flash based solutions
>> the price comparison evens itself out even more.
>
>check your SSD specs, some of the high performance ones draw quite a bit
>of power.
>
>David Lang
>
>
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