linux-raid.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Simon Valiquette <v.simon@ieee.org>
To: turbo@weasel.com
Cc: linux-raid@vger.kernel.org
Subject: Re: nested raid possible?
Date: Fri, 06 Jul 2007 01:49:58 -0400	[thread overview]
Message-ID: <468DD806.6070608@ieee.org> (raw)
In-Reply-To: <8585506.1183693119573.JavaMail.root@wombat.diezmil.com>

turbo@weasel.com un jour écrivit:
> I have a raid-5 array of six 250gb hard drives.
> I just bought four 500gb hard drives.
> 
> I know I can take the six drives and make three raid-1 arrays of 500gb.

   Here, you probably means three RAID-0 arrays of 500GB, otherwise you 
would get three RAID-1 of 250GB.

> After doing that, can I make a raid-5 array consisting of the three 
> raid-0 arrays, and the four 500gb hard drives?

   Yes, It would works, because all you need is to get a block device. 
Software Raid takes many block devices to generate one block device, so It 
is transparent.

   That said, I don't say that It is a good idea to do It as you are 
suggesting.  You realize that It would be less reliable than a RAID-5 
array made of seven 500GB drive.

   If you really want to do than, I would feel more confident using 
RAID-6.   Another option is to use RAID-10 with 4x250GB with 2 hot spare, 
and connect everything in a RAID-5 array for a total of also 2.5TB of 
usable space.  Personnaly, considering the price of the hard drives, I 
won't ever bother and use only 500GB drive.

   That said, It is your data.  It is you that know if It is better to 
have the full 3TB, at the cost of somewhat more risk to loose your data. 
Maybe the additional risk is low enough for your needs, I don't know.

   But in a business environment, I would normaly not do It.

Simon Valiquette

-
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

  reply	other threads:[~2007-07-06  5:49 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-07-06  3:38 nested raid possible? turbo
2007-07-06  5:49 ` Simon Valiquette [this message]
2007-07-06  7:57   ` David Greaves
2007-07-07 14:12 ` Bill Davidsen

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=468DD806.6070608@ieee.org \
    --to=v.simon@ieee.org \
    --cc=linux-raid@vger.kernel.org \
    --cc=turbo@weasel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).