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From: Luca Berra <bluca@comedia.it>
To: linux-raid@vger.kernel.org
Subject: Re: raid and power off savety
Date: Wed, 23 Mar 2005 21:12:18 +0100	[thread overview]
Message-ID: <20050323201218.GC26683@percy.comedia.it> (raw)
In-Reply-To: <76592C4D3DA1AC4FB8424084D10D31A806115268@mchh2c4e.mchh.siemens.de>

On Tue, Mar 22, 2005 at 12:29:57PM +0100, Schuett Thomas EXT wrote:
Define RAID,
I will answer for RAID = MD driver, but hw raid solutions might have
different answers (eg battery backed up cache)

>If you think through system crash scenarios, what types of chrashes 
>are you are thinking of? Do you only consider harddisk faults, or 
>do you consider power failures as well?
md protects against disk failures

>Or more extreme: Does RAID gives you savety on HD HW failures, but may
>make things worse for power failures (hard power switch off)?
a power failure _might_ make things worse

>Or more academic: Does raid have some journaling of its dirty cache 
>(and/or whatever would need to be journaled) in a non volatile way,
>or isn't there any need for it for any tricky reason?
there isn't one for lack of a non-volatile storage for dirty cache

-- 
Luca Berra -- bluca@comedia.it
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  reply	other threads:[~2005-03-23 20:12 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-03-22 11:29 raid and power off savety Schuett Thomas EXT
2005-03-23 20:12 ` Luca Berra [this message]
2005-03-23 21:26 ` Gordon Henderson

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