From: Neil Brown <neilb@suse.de>
To: "Mr. James W. Laferriere" <babydr@baby-dragons.com>
Cc: linux-raid maillist <linux-raid@vger.kernel.org>
Subject: Re: very degraded RAID5, or increasing capacity by adding discs
Date: Wed, 10 Oct 2007 07:52:41 +1000 [thread overview]
Message-ID: <18187.63529.526020.305681@notabene.brown> (raw)
In-Reply-To: message from Mr. James W. Laferriere on Tuesday October 9
On Tuesday October 9, babydr@baby-dragons.com wrote:
> Hello Neil ,
>
> On Tue, 9 Oct 2007, Neil Brown wrote:
> > On Tuesday October 9, janek_listy@wp.pl wrote:
> >>
> >> Problems at step 4.: 'man mdadm' doesn't tell if it's possible to
> >> grow an array to a degraded array (non existant disc). Is it possible?
> >
> > Why not experiment with loop devices on files and find out?
> >
> > But yes: you can grow to a degraded array providing you specify a
> > --backup-file.
> Is there an estimate of how large this file can get ?
> It's probably a calculation based on disk & array parameters .
> But I was unable to find a reference on it from the manpage .
>
> Tia , JimL
I think:
chunk-size * old-ndisks * new-ndisks * 2 + 1K
It might be smaller than that, but it shouldn't be larger.
NeilBrown
next prev parent reply other threads:[~2007-10-09 21:52 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-08 19:13 very degraded RAID5, or increasing capacity by adding discs Janek Kozicki
2007-10-08 19:17 ` Justin Piszcz
2007-10-08 19:26 ` Richard Scobie
2007-10-08 20:08 ` Guy Watkins
2007-10-08 22:25 ` Janek Kozicki
2007-10-08 22:46 ` Janek Kozicki
2007-10-09 1:53 ` Guy Watkins
2007-10-09 3:32 ` Neil Brown
2007-10-09 14:44 ` Janek Kozicki
2007-10-09 14:56 ` Mr. James W. Laferriere
2007-10-09 21:52 ` Neil Brown [this message]
2007-10-08 22:52 ` Michael Tokarev
2007-10-09 3:24 ` Neil Brown
2007-10-09 9:48 ` Michael Tokarev
2007-10-22 9:03 ` Louis-David Mitterrand
2007-10-23 22:41 ` Bill Davidsen
2007-10-09 14:42 ` Janek Kozicki
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