From: Daniel Pittman <daniel@rimspace.net>
To: linux-raid@vger.kernel.org
Subject: Re: RAID 5 questions
Date: Sun, 01 Aug 2004 13:08:34 +1000 [thread overview]
Message-ID: <871xira72l.fsf@enki.rimspace.net> (raw)
In-Reply-To: 1091325475.2374.11.camel@localhost
On 1 Aug 2004, Ninti Systems wrote:
> I'm about to embark on building a RAID 5 Linux software array with 4
> disks (I've only ever built 2 disk RAID 1 arrays before).
>
> Q1: Is it true that Linux can't/shouldn't boot off a RAID 5 array?
Grub certainly can't boot of a software RAID-5 array, and I don't
believe that lilo can either. This is because of these tools not
understanding the RAID-5 disk layout, not any other limitation.
> Q2: The four disks have identical manufacturer, model and size, but two
> are brand new while two have had NTFS filesystems on them. Accordingly,
> if I run hdparm -g on them, two disks have these specs:
>
> geometry = 2498/255/63, sectors = 40132503, start = 0
>
> while the other two disks have these specs:
>
> geometry = 39813/16/63, sectors = 40132503, start = 0
>
> Is this an issue with software RAID?
No. Software RAID, unlike hardware raid, cares only that you have enough
blocks on the disk. You don't need to match *any* other characteristic
of the disks, and not even that if you don't mind wasting a few bytes.
Daniel
--
The PC is the LSD of the '90s.
-- Timothy Leary, __Guardian_ (June 1, 1996)
next prev parent reply other threads:[~2004-08-01 3:08 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-08-01 1:57 RAID 5 questions Ninti Systems
2004-08-01 3:08 ` Daniel Pittman [this message]
2004-08-01 3:31 ` Jim Paris
2004-08-01 3:50 ` Alvin Oga
2004-08-02 6:01 ` Jarmo Järvenpää
2004-08-02 6:08 ` Luca Berra
2004-08-02 6:55 ` Jarmo Järvenpää
2004-08-02 6:09 ` Jim Paris
2004-08-02 7:27 ` Jarmo Järvenpää
2004-08-03 20:23 ` Frank van Maarseveen
2004-08-04 8:52 ` Tim Small
2004-08-01 9:33 ` Luca Berra
2004-08-01 10:24 ` Frank van Maarseveen
2004-08-03 5:19 ` misty-
2004-08-06 0:49 ` H. Peter Anvin
-- strict thread matches above, loose matches on Subject: below --
2004-06-03 14:29 Raid " David Greaves
2004-06-03 15:13 ` Guy
2004-06-03 15:50 ` David Greaves
2004-06-03 16:43 ` Guy
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