From: Dave Crooke <dcrooke@gmail.com>
To: Yeb Havinga <yebhavinga@gmail.com>
Cc: Francisco Reyes <lists@stringsutils.com>
Cc: Pgsql performance <pgsql-performance@postgresql.org>
Subject: Re: 10K vs 15k rpm for analytics
Date: Tue, 2 Mar 2010 15:05:07 -0600
Message-ID: <ca24673e1003021305p7014202dj3c5a2ff575ce4e83@mail.gmail.com> (raw)
In-Reply-To: <4B8D7A6C.3010304@gmail.com>
References: <cone.1267562557.293175.32557.1000@shelca>
<4B8D7A6C.3010304@gmail.com>
Seconded .... these days even a single 5400rpm SATA drive can muster almost
100MB/sec on a sequential read.
The benefit of 15K rpm drives is seen when you have a lot of small, random
accesses from a working set that is too big to cache .... the extra
rotational speed translates to an average reduction of about 1ms on a random
seek and read from the media.
Cheers
Dave
On Tue, Mar 2, 2010 at 2:51 PM, Yeb Havinga <yebhavinga@gmail.com> wrote:
> Francisco Reyes wrote:
>
>> Anyone has any experience doing analytics with postgres. In particular if
>> 10K rpm drives are good enough vs using 15K rpm, over 24 drives. Price
>> difference is $3,000.
>>
>> Rarely ever have more than 2 or 3 connections to the machine.
>>
>> So far from what I have seen throughput is more important than TPS for the
>> queries we do. Usually we end up doing sequential scans to do
>> summaries/aggregates.
>>
>> With 24 drives it'll probably be the controller that is the limiting
> factor of bandwidth. Our HP SAN controller with 28 15K drives delivers
> 170MB/s at maximum with raid 0 and about 155MB/s with raid 1+0. So I'd go
> for the 10K drives and put the saved money towards the controller (or maybe
> more than one controller).
>
> regards,
> Yeb Havinga
>
>
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Subject: Re: 10K vs 15k rpm for analytics
In-Reply-To: <ca24673e1003021305p7014202dj3c5a2ff575ce4e83@mail.gmail.com>
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