From: NeilBrown <neilb@suse.com>
To: Wols Lists <antlists@youngman.org.uk>, Nix <nix@esperi.org.uk>
Cc: linux-raid@vger.kernel.org
Subject: Re: 4.11.2: reshape raid5 -> raid6 atop bcache deadlocks at start on md_attr_store / raid5_make_request
Date: Wed, 24 May 2017 11:50:17 +1000 [thread overview]
Message-ID: <87mva3hvl2.fsf@notabene.neil.brown.name> (raw)
In-Reply-To: <59244B95.4080600@youngman.org.uk>
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On Tue, May 23 2017, Wols Lists wrote:
> Thanks. I've updated the section. I've taken pretty much everything
> you've said, but rewritten it in my own words, so that the page remains
> consistent in style. I hope I haven't missed anything.
>
> It's thrown up two little points I've noted on the page - if a v1.0
> mirror has its offset changed, does this break the linux boot? (that's
> the "without an initramfs" boot that doesn't assemble the mirror until
> after the kernel is running).
Yes, if a v1.0 has a data offset that wasn't zero, you wouldn't be able
to boot of a member device.
But there is no good reason that I can think of to change the data
offset of a device in a RAID1.
>
> And if you shut down cleanly during a backup-file reshape, is this fact
> noted or does mdadm just assume any shutdown is dirty and use the backup
> file anyway?
The backup file contains UUID and version info.
When mdadm determines that part of the backup is no longer needed, it
invalidates the backup before enabling writes to that region of the
array.
So it only uses the file is there is good reason to suspect that it is
both necessary and safe. (It may not always be necessary. It should
always be safe).
NeilBrown
>
> Cheers,
> Wol
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next prev parent reply other threads:[~2017-05-24 1:50 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-22 9:13 4.11.2: reshape raid5 -> raid6 atop bcache deadlocks at start on md_attr_store / raid5_make_request Nix
2017-05-22 11:35 ` NeilBrown
2017-05-22 15:30 ` Nix
2017-05-22 19:07 ` Wols Lists
2017-05-22 20:43 ` Nix
2017-05-23 1:20 ` NeilBrown
2017-05-23 10:10 ` Nix
2017-05-23 1:39 ` NeilBrown
2017-05-23 14:47 ` Wols Lists
2017-05-24 1:50 ` NeilBrown [this message]
2017-05-23 1:07 ` NeilBrown
2017-05-22 21:38 ` Nix
2017-05-23 14:16 ` Wols Lists
2017-05-23 15:00 ` Nix
2017-05-24 1:24 ` NeilBrown
2017-05-24 13:28 ` Nix
2017-05-25 1:31 ` NeilBrown
2017-05-25 12:14 ` Nix
2017-05-24 19:42 ` Nix
2017-05-24 22:57 ` Shaohua Li
2017-05-25 1:30 ` NeilBrown
2017-05-25 1:46 ` Shaohua Li
2017-05-26 3:23 ` NeilBrown
2017-05-26 16:40 ` Shaohua Li
2017-05-28 23:17 ` NeilBrown
2017-05-30 17:41 ` Shaohua Li
2017-06-05 6:49 ` [PATCH] md: fix deadlock between mddev_suspend() and md_write_start() NeilBrown
2017-06-06 0:01 ` Shaohua Li
2017-06-07 1:45 ` NeilBrown
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