Re: Completely un-tuned Postgresql benchmark results: SSD vs desktop HDD - Mailing list pgsql-performance

From Scott Marlowe
Subject Re: Completely un-tuned Postgresql benchmark results: SSD vs desktop HDD
Date
Msg-id AANLkTi=vPV4mfDFKUmYNK7avf8owS6RfKBt43_ypVBDk@mail.gmail.com
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In response to Re: Completely un-tuned Postgresql benchmark results: SSD vs desktop HDD  (Michael March <mmarch@gmail.com>)
List pgsql-performance
On Sun, Aug 8, 2010 at 12:49 AM, Michael March <mmarch@gmail.com> wrote:
>
>> SSD's actually vary quite a bit with typical postgres benchmark workloads.
>
> You mean various SSDs from different vendors? Or are you saying the same SSD
> model might vary in performance from drive to drive?
>
>>
>>  Many of them also do not guarantee data that has been sync'd will not be
>> lost if power fails (most hard drives with a sane OS and file system do).
>
> What feature does an SSD need to have to insure that sync'd data is indeed
> written to the SSD in the case of power loss?

A big freaking capacitor and the ability to notice power's been cut
and start writing out the cache.  There are a few that have it that
are coming out right about now.  There was a post about one such drive
a few days ago, it was like 50G and $450 or so, so not cheap, but not
that bad compared to the $7000 drive bays with 16 15k6 drives I've
used in to the past to get good performance (3 to 4k tps)

--
To understand recursion, one must first understand recursion.

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