From: Ross Vandegrift <ross@willow.seitz.com>
To: Gregory Leblanc <gleblanc@linuxweasel.com>
Cc: linux-raid@vger.kernel.org
Subject: Re: RAID-6 support in kernel?
Date: Mon, 3 Jun 2002 15:53:24 -0400 [thread overview]
Message-ID: <20020603195324.GA11678@willow.seitz.com> (raw)
In-Reply-To: <1023125615.1051.1283.camel@peecee>
> > It'll waste 9 drives, giving me a total capacity of 7n instead of 14n.
> > And, by definition, RAID-6 _can_ withstand _any_ two-drive failure.
>
> This is certainly not true.
>
> Combining N RAID-5 into a stripe wastes on N disks.
>
> Hot spares are quite a nice way to increase the reliability of your
> arrays, somewhat. You can still be in trouble if a second disk fails
> before the resync finishes, but at that point you're probably talking
> about something of a more catastrophic failure, perhaps outside of the
> machine itself.
This could become a lot less of an issue. I recall Neil Brown recently
mentioning that he was thinking about journalling RAID code. This would
do away with long resyncs much like journalling filesystems did away
with long fscks. Obviously, I'm not sure if it's something he'll
decide to do or not, but it would really increase the viability of hot
spares.
Ross Vandegrift
ross@willow.seitz.com
next prev parent reply other threads:[~2002-06-03 19:53 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-06-02 23:01 RAID-6 support in kernel? Roy Sigurd Karlsbakk
2002-06-03 0:33 ` Derek Vadala
2002-06-03 8:24 ` Roy Sigurd Karlsbakk
2002-06-03 9:25 ` Derek Vadala
[not found] ` <Pine.GSO.4.21.0206030213510.23709-100000@gecko.roadtoad.net>
2002-06-03 9:31 ` Vojtech Pavlik
2002-06-03 14:52 ` Kasper Dupont
2002-06-03 14:55 ` Vojtech Pavlik
2002-06-04 12:49 ` Roy Sigurd Karlsbakk
2002-06-04 15:49 ` Pavel Machek
2002-06-04 15:49 ` Pavel Machek
[not found] ` <20020604154904.J36@toy.ucw.cz>
2002-06-04 22:27 ` Kasper Dupont
2002-06-05 9:28 ` Roy Sigurd Karlsbakk
[not found] ` <3CFD3EE5.DAE3E2C9@daimi.au.dk>
2002-06-05 9:36 ` Roy Sigurd Karlsbakk
2002-06-03 17:33 ` Gregory Leblanc
2002-06-03 19:53 ` Ross Vandegrift [this message]
2002-06-04 20:20 ` Jakob Østergaard
2002-06-05 7:57 ` Luca Berra
2002-06-05 10:53 ` Jakob Østergaard
2002-06-05 19:42 ` Luca Berra
2002-06-05 21:25 ` background scanning for media defects (was Re: RAID-6 support in kernel?) Friedrich Lobenstock
2002-06-04 18:50 ` RAID-6 support in kernel? Bill Davidsen
[not found] <Pine.LNX.3.96.1020604144204.5024D-100000@gatekeeper.tmr.com>
2002-06-06 1:19 ` Derek Vadala
2002-06-06 8:28 ` Kasper Dupont
2002-06-06 11:57 ` Helge Hafting
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