From: Roman Mamedov <rm@romanrm.ru>
To: Beolach <beolach@gmail.com>
Cc: Lasse Jensen <fafler@gmail.com>, linux-raid@vger.kernel.org
Subject: Re: Upgrading from RAID 5 to 6 or build native level 6?
Date: Sat, 19 Feb 2011 17:28:42 +0500 [thread overview]
Message-ID: <20110219172842.5bc79f44@natsu> (raw)
In-Reply-To: <AANLkTikqytG1S1nU0NkZSjcEs08kyDFUUKpfgxGerQn7@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 1074 bytes --]
On Fri, 18 Feb 2011 19:02:07 -0700
Beolach <beolach@gmail.com> wrote:
> That information is incomplete or out-of-date. During a RAID 5 to
> RAID 6 reshape, there may be an intermediate step where all of the Q
> parity blocks are stored on one disk, but as the reshape continues, it
> will move all the Q parity blocks to a normal RAID 6 layout. IIRC, in
> the very early stages of RAID 5 to RAID 6 reshape development, it
> would leave it in the abnormal layout, but that has not been the case
> for quite some time. And I believe in some cases a RAID 5 to RAID 6
> reshape will not even use the intermediate step w/ the abnormal
> layout. After the reshape fully completes, it is exactly the same as
> a RAID 6 array built from scratch.
See man mdadm --layout=preserve vs --layout=normalise.
I am not sure which one of these is the default, but it is definitely still
possible to convert RAID5 to RAID6 (while adding one disk) without restriping,
and to me this looks like a very useful feature, not something outdated.
--
With respect,
Roman
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 198 bytes --]
prev parent reply other threads:[~2011-02-19 12:28 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-16 15:40 Upgrading from RAID 5 to 6 or build native level 6? Lasse Jensen
2011-02-19 2:02 ` Beolach
2011-02-19 12:28 ` Roman Mamedov [this message]
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=20110219172842.5bc79f44@natsu \
--to=rm@romanrm.ru \
--cc=beolach@gmail.com \
--cc=fafler@gmail.com \
--cc=linux-raid@vger.kernel.org \
/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).