From: Mark Kirkwood <markir@paradise.net.nz>
To: carlosreimer@terra.com.br
Cc: Mark Lewis <mark.lewis@mir3.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-performance@postgresql.org
Subject: Re: RES: Initial database loading and IDE x SCSI
Date: Sat, 03 Jun 2006 12:13:27 +1200
Message-ID: <4480D427.50207@paradise.net.nz> (raw)
In-Reply-To: <1149279209.20798.108.camel@archimedes>
References: <PEEPKDFEHHEMKBBFPOOKCEHFCPAA.carlosreimer@terra.com.br>
<1149279209.20798.108.camel@archimedes>
Mark Lewis wrote:
>
> The naive approach works on IDE drives because they don't (usually)
> honor the request to write the data immediately, so it can fill its
> write cache up with several megabytes of data and write it out to the
> disk at its leisure.
>
FWIW - If you are using MacOS X or Windows, then later SATA (in
particular, not sure about older IDE) will honor the request to write
immediately, even if the disk write cache is enabled.
I believe that Linux 2.6+ and SATA II will also behave this way (I'm
thinking that write barrier support *is* in 2.6 now - however you would
be wise to follow up on the Linux kernel list if you want to be sure!)
In these cases data integrity becomes similar to SCSI - however, unless
you buy SATA specifically designed for a server type workload (e.g WD
Raptor), then ATA/SATA tend to fail more quickly if used in this way
(e.g. 24/7, hot/dusty environment etc).
Cheers
Mark
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To: pgsql-performance@postgresql.org
Cc: markir@paradise.net.nz, carlosreimer@terra.com.br, mark.lewis@mir3.com, tgl@sss.pgh.pa.us
Subject: Re: RES: Initial database loading and IDE x SCSI
In-Reply-To: <4480D427.50207@paradise.net.nz>
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