Message-ID: <44D91D17.30106@commandprompt.com>
Date: Tue, 08 Aug 2006 16:24:07 -0700
From: "Joshua D. Drake" <jd@commandprompt.com>
Organization: Command Prompt, Inc.
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To: "Thomas F. O'Connell" <tfo@sitening.com>
CC: Kenji Morishige <kenjim@juniper.net>, pgsql-performance@postgresql.org
Subject: Re: most bang for buck with ~ $20,000
References: <20060808204354.GN29379@juniper.net>
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	<9EE66C7F-0B04-4472-9EBD-CD567AC9EA1D@sitening.com>
	<44D90FFE.7010807@commandprompt.com>
	<82C06632-148B-4489-90EB-BBB8A6BD1159@sitening.com>
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> 
> In which case, which is theoretically better (since I don't have a 
> convenient test bed at the moment) for WAL in a write-heavy environment? 
> More disks in a RAID 10 (which should theoretically improve write 
> throughput in general, to a point) or a 2-disk RAID 1? Does it become a 
> price/performance question, or is there virtually no benefit to throwing 
> more disks at RAID 10 for WAL if you turn off journaling on the filesystem?

Over 4 drives, I would gather that RAID 10 wouldn't gain you anything. 
Possibly over 6 or 8 however, it may be faster because you are writing 
smaller chunks of data, even if two copies of each.

Sincerely,

Joshua D. Drake


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