From: Wols Lists <antlists@youngman.org.uk>
To: NeilBrown <neilb@suse.com>,
Johannes Thumshirn <jthumshirn@suse.de>,
lsf-pc@lists.linux-foundation.org
Cc: linux-raid@vger.kernel.org, linux-block@vger.kernel.org,
Hannes Reinecke <hare@suse.de>, Neil Brown <neilb@suse.de>
Subject: Re: [LSF/MM TOPIC] De-clustered RAID with MD
Date: Tue, 30 Jan 2018 10:43:37 +0000 [thread overview]
Message-ID: <5A704C59.4000705@youngman.org.uk> (raw)
In-Reply-To: <87fu6o5o83.fsf@notabene.neil.brown.name>
On 29/01/18 21:50, NeilBrown wrote:
> By doing declustered parity you can sanely do raid6 on 100 drives, using
> a logical stripe size that is much smaller than 100.
> When recovering a single drive, the 10-groups-of-10 would put heavy load
> on 9 other drives, while the decluster approach puts light load on 99
> other drives. No matter how clever md is at throttling recovery, I
> would still rather distribute the load so that md has an easier job.
Not offering to do it ... :-)
But that sounds a bit like linux raid-10. Could a simple approach be to
do something like "raid-6,11,100", ie raid-6 with 9 data chunks, two
parity, striped across 100 drives? Okay, it's not as good as the
decluster approach, but it would spread the stress of a rebuild across
20 drives, not 10. And probably be fairly easy to implement.
Cheers,
Wol
next prev parent reply other threads:[~2018-01-30 10:43 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-29 15:23 [LSF/MM TOPIC] De-clustered RAID with MD Johannes Thumshirn
2018-01-29 15:23 ` Johannes Thumshirn
2018-01-29 16:32 ` Wols Lists
2018-01-29 21:50 ` [Lsf-pc] " NeilBrown
2018-01-29 21:50 ` NeilBrown
2018-01-30 10:43 ` Wols Lists [this message]
2018-01-30 11:24 ` NeilBrown
2018-01-30 17:40 ` Wol's lists
2018-02-03 15:53 ` Wols Lists
2018-02-03 17:16 ` Wols Lists
2018-01-31 9:58 ` [Lsf-pc] " David Brown
2018-01-31 9:58 ` David Brown
2018-01-31 10:58 ` Johannes Thumshirn
2018-01-31 14:27 ` Wols Lists
2018-01-31 14:41 ` David Brown
2018-01-30 9:40 ` [Lsf-pc] " Johannes Thumshirn
2018-01-30 9:40 ` Johannes Thumshirn
2018-01-31 8:03 ` David Brown
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=5A704C59.4000705@youngman.org.uk \
--to=antlists@youngman.org.uk \
--cc=hare@suse.de \
--cc=jthumshirn@suse.de \
--cc=linux-block@vger.kernel.org \
--cc=linux-raid@vger.kernel.org \
--cc=lsf-pc@lists.linux-foundation.org \
--cc=neilb@suse.com \
--cc=neilb@suse.de \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.