Re: Six PostgreSQL questions from a pokerplayer

Mark Kirkwood <markir@paradise.net.nz>

From: Mark Kirkwood <markir@paradise.net.nz>
To: Craig Ringer <craig@postnewspapers.com.au>
Cc: Patvs <patvs@chello.nl>, pgsql-performance@postgresql.org
Date: 2009-07-06T06:13:12Z
Lists: pgsql-performance
Craig Ringer wrote:
> On Sat, 2009-07-04 at 11:51 -0700, Patvs wrote:
>
>
>   
>> With 4 regular harddisks in RAID0 you get great read/write speeds, but the
>> SSDs excel in IO/s and a 0.1ms access time.
>>     
>
> ... but are often really, really, really, really slow at writing. The
> fancier ones are fast at writing but generally slow down over time.
>
>   

Also, (probably pointing out the obvious here) to be on the safe side 
you should avoid RAID0 for any data that is important to you - as it's 
pretty easy to get one bad disk straight from new!

With respect to SSD's one option for a small sized database is 2xSSD in 
RAID1 - provided they are the *right* SSD that is, which at this point 
in time seems to be the Intel X25E. Note that I have not benchmarked 
this configuration, so no guarantees that it (or the Intel SSDs 
themselves) are as good as the various on-the-web tests indicate!

regards

Mark