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Re: Hardware vs Software RAID

From: Matthew Wakeling <matthew(at)flymine(dot)org>
To: Pgsql performance <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Hardware vs Software RAID
Date: 2008-06-27 11:00:25
Message-ID: Pine.LNX.4.64.0806271143281.4085@aragorn.flymine.org (view raw or flat)
Thread:
Lists: pgsql-performance
On Thu, 26 Jun 2008, Merlin Moncure wrote:
> In addition there are many different types of flash (MLC/SLC) and the 
> flash cells themselves can be organized in particular ways involving 
> various trade-offs.

Yeah, I wouldn't go for MLC, given it has a tenth the lifespan of SLC.

> The main issue is lousy random write performance that basically makes 
> them useless for any kind of OLTP operation.

For the mentioned device, they claim a sequential read speed of 100MB/s, 
sequential write speed of 80MB/s, random read speed of 80MB/s and random 
write speed of 30MB/s. This is *much* better than figures quoted for many 
other devices, but of course unless they publish the block size they used 
for the random speed tests, the figures are completely useless.

Matthew

-- 
sed -e '/^[when][coders]/!d;/^...[discover].$/d;/^..[real].[code]$/!d
' <`locate dict/words`

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Next:From: Merlin MoncureDate: 2008-06-27 13:16:13
Subject: Re: Hardware vs Software RAID
Previous:From: Joshua D. DrakeDate: 2008-06-27 06:21:31
Subject: Re: Hardware suggestions for high performance 8.3

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