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From: Francisco Reyes <lists@stringsutils.com>
To: Yeb Havinga <yebhavinga@gmail.com>
Cc: Pgsql performance <pgsql-performance@postgresql.org>
Subject: Re: 10K vs 15k rpm for analytics
Date: Tue, 02 Mar 2010 16:28:35 -0500
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Yeb Havinga writes:

> With 24 drives it'll probably be the controller that is the limiting 
> factor of bandwidth.

Going with a 3Ware SAS controller.

> Our HP SAN controller with 28 15K drives delivers 
> 170MB/s at maximum with raid 0 and about 155MB/s with raid 1+0. 


Already have simmilar machine in house.
With RAID 1+0 Bonne++ reports around 400MB/sec sequential read.

> go for the 10K drives and put the saved money towards the controller (or 
> maybe more than one controller).

Have some external enclosures with 16 15Krpm drives. They are older  15K 
rpms, but they should be good enough. 

Since the 15K rpms usually have better Transanctions per second I will 
put WAL and indexes in the external enclosure.