Re: raid10 hard disk choice - Mailing list pgsql-performance

From Craig James
Subject Re: raid10 hard disk choice
Date
Msg-id 4A158B07.2080702@emolecules.com
Whole thread Raw
In response to Re: raid10 hard disk choice  (Matthew Wakeling <matthew@flymine.org>)
List pgsql-performance
Matthew Wakeling wrote:
> On Thu, 21 May 2009, Linos wrote:
>>     i have to buy a new server and in the budget i have (small) i have
>> to select one of this two options:
>>
>> -4 sas 146gb 15k rpm raid10.
>> -8 sas 146gb 10k rpm raid10.
>
> It depends what you are doing. I think in most situations, the second
> option is better, but there may be a few situations where the reverse is
> true.
>
> Basically, the first option will only be faster if you are doing lots of
> seeking (small requests) in a single thread. As soon as you go
> multi-threaded or are looking at sequential scans, you're better off
> with more discs.

Since you have to share the disks with a file server, which might be heavily used, the 8-disk array will probably be
bettereven if you're doing lots of seeking in a single thread. 

Craig

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