Re: hanging for 30sec when checkpointing

From: "Peter Galbavy" <peter(dot)galbavy(at)knowtion(dot)net>
To: "scott(dot)marlowe" <scott(dot)marlowe(at)ihs(dot)com>
Cc: "Iain" <iain(at)mst(dot)co(dot)jp>, "Shane Wright" <me(at)shanewright(dot)co(dot)uk>, <pgsql-admin(at)postgresql(dot)org>
Subject: Re: hanging for 30sec when checkpointing
Date: 2004-02-10 09:22:37
Message-ID: 014601c3efb7$6da04720$24e0a8c0@sonylaptop
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scott.marlowe wrote:
> I don't know who you think you are, but I've physically tested the
> stuff I'm talking about. Care to qualify what you mean?

I would genuinely be interested in seeing the results and the methodology.

> IDE drives (all the ones I've ever tested) LIE about their write
> caches and fsync. don't believe me? Simple, hook one up, initiate
> 100 parallel transactions, pull the power plug, watch your database
> fail to come back up due to the corruption caused by the LYING IDE
> drives.

See my comment/question below.

> Do the same with SCSI. watch the database come right back to life.
>
> If you're gonna accuse me of lying, you damned well better have the
> balls AND evidence to back it up.

I am NOT accussing anyone of lying, least of all people I don't personally
know, and certainly not you. What I am referring to is over-generalisation.
You made a long and detailed generalisation, without detailing anything.

My primary question, without seeing the way you did it, is can you comment
on whether you wrote your own testbed or did you rely on potentially flawed
OS interfaces ? Did you use a signal analyser ?

Now, I have *not* done the tests - hence my real interest, but I have had at
least as many problems with SCSI sub-systems as with IDE over the years.
Probably more actually. Ever since using IBM EIDE drives (the 75GXP
included, I am a lucky one) I have had very little, knock on wood, to worry
about even during power failures.

Peter

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