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To: "James Mansion" <james@mansionfamily.plus.com>, "Hannu Krosing"
	<hannu@2ndquadrant.com>
Cc: "Yeb Havinga" <yebhavinga@gmail.com>, "Greg Smith" <greg@2ndquadrant.com>,
	"Tom Lane" <tgl@sss.pgh.pa.us>, "Ross J. Reedstrom" <reedstrm@rice.edu>,
	pgsql-performance@postgresql.org
Subject: Re: mysql to postgresql, performance questions
References: <4BA23936.2030507@gmail.com> <4BA596D2.4050406@squeakycode.net>
	<20100323185232.GD6662@rice.edu> <5342.1269372121@sss.pgh.pa.us>
	<4BA934B9.9070401@2ndquadrant.com> <4BA9D39B.6020103@gmail.com>
	<1269421198.11473.50.camel@hvost>
	<4BABC1E0.7010607@mansionfamily.plus.com>
Date: Thu, 25 Mar 2010 21:29:44 +0100
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From: "Pierre C" <lists@peufeu.com>
Message-ID: <op.u944juqoeorkce@localhost>
In-Reply-To: <4BABC1E0.7010607@mansionfamily.plus.com>
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> Hannu Krosing wrote:
>> Pulling the plug should not corrupt a postgreSQL database, unless it was
>> using disks which lie about write caching.
>>
> Didn't we recently put the old wife's 'the disks lied' tale to bed in  
> favour of actually admiting that some well known filesystems and  
> saftware raid systems have had trouble with their write barriers?

I put a cheap UPS on the home server (which uses Software RAID) precisely  
because I don't really trust that stuff, and there is also the RAID5 write  
hole... and maybe the RAID1 write hole too... and installing a UPS takes  
less time that actually figuring out if the system is power-loss-safe.