From: NeilBrown <neilb@suse.de>
To: Alexander Lyakas <alex.bolshoy@gmail.com>
Cc: linux-raid@vger.kernel.org
Subject: Re: [md PATCH 08/23] md: don't set md arrays to readonly on shutdown.
Date: Thu, 19 Apr 2012 08:48:33 +1000 [thread overview]
Message-ID: <20120419084833.39379a6f@notabene.brown> (raw)
In-Reply-To: <CAGRgLy5UYf27335hQmEQQ8V2GSatQ-1aev9DdTia0j-Hv4wsEg@mail.gmail.com>
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On Wed, 18 Apr 2012 18:37:56 +0300 Alexander Lyakas <alex.bolshoy@gmail.com>
wrote:
> Hi Neil,
>
> > This could result in the shutdown happening when array is marked
> > dirty, thus forcing a resync on reboot. However if you reboot
> > without performing a "sync" first, you get to keep both halves.
> Can you pls clarify the last statement?
"If you break it, you get to keep both halves" is a colloquial phrase meaning
that that the person saying it takes no responsibility for any damage that
the person being spoken to causes.
When applied to software issues it is ironic (because when a thing 'breaks' it
doesn't result in two pieces like, for example, when a plate breaks) and so
funny (I hope).
(when applied to a RAID mirror, it is doubly ironic :-)
If you force a fast shutdown without allowing a sync to happen
(e.g. reboot -f -n) there could be data on the way out to the array when the
system actually reboots, so the array will be dirty, so a resync will be
required when the system restarts.
This might be undesirable, but that isn't my problem and is not the problem
of md/raid. Rather the cause of the problem is the "reboot -f -n". i.e.
"your" problem. "You" broke it, you get to keep both halves.
Does that help?
NeilBrown
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next prev parent reply other threads:[~2012-04-18 22:48 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-14 4:40 [md PATCH 00/23] md patches heading for 3.4 NeilBrown
2012-03-14 4:40 ` [md PATCH 04/23] md: Use existed macros instead of numbers NeilBrown
2012-03-14 4:40 ` [md PATCH 02/23] md/raid10: remove unnecessary smp_mb() from end_sync_write NeilBrown
2012-03-14 4:40 ` [md PATCH 05/23] md/raid5: use atomic_dec_return() instead of atomic_dec() and atomic_read() NeilBrown
2012-03-14 4:40 ` [md PATCH 01/23] md/raid5: make sure reshape_position is cleared on error path NeilBrown
2012-03-14 4:40 ` [md PATCH 03/23] md/raid5: removed unused 'added_devices' variable NeilBrown
2012-03-14 4:40 ` [md PATCH 06/23] md: allow last device to be forcibly removed from RAID1/RAID10 NeilBrown
2012-03-14 4:40 ` [md PATCH 13/23] md/raid10: handle merge_bvec_fn in member devices NeilBrown
2012-03-14 4:40 ` [md PATCH 11/23] md: tidy up rdev_for_each usage NeilBrown
2012-03-14 4:40 ` [md PATCH 07/23] md: allow re-add to failed arrays NeilBrown
2012-03-14 4:40 ` [md PATCH 10/23] md/raid1, raid10: avoid deadlock during resync/recovery NeilBrown
2012-03-14 4:40 ` [md PATCH 08/23] md: don't set md arrays to readonly on shutdown NeilBrown
2012-04-18 15:37 ` Alexander Lyakas
2012-04-18 17:44 ` Paweł Brodacki
2012-04-18 20:53 ` Alexander Lyakas
2012-04-18 22:48 ` NeilBrown [this message]
2012-04-19 9:11 ` Alexander Lyakas
2012-04-19 9:57 ` NeilBrown
2012-04-20 11:30 ` Paweł Brodacki
2012-04-20 12:01 ` NeilBrown
2012-04-21 15:18 ` Paweł Brodacki
2012-04-21 20:42 ` NeilBrown
2012-04-30 10:32 ` Paweł Brodacki
2012-04-20 16:26 ` John Robinson
2012-03-14 4:40 ` [md PATCH 14/23] md/raid1: handle merge_bvec_fn in member devices NeilBrown
2012-03-14 4:40 ` [md PATCH 12/23] md: add proper merge_bvec handling to RAID0 and Linear NeilBrown
2012-03-14 4:40 ` [md PATCH 09/23] md/bitmap: ensure to load bitmap when creating via sysfs NeilBrown
2012-03-14 4:40 ` [md PATCH 16/23] md/bitmap: remove some unused noise from bitmap.h NeilBrown
2012-03-14 4:40 ` [md PATCH 20/23] md/bitmap: remove unnecessary indirection when allocating NeilBrown
2012-03-14 4:40 ` [md PATCH 22/23] md: fix clearing of the 'changed' flags for the bad blocks list NeilBrown
2012-03-14 4:40 ` [md PATCH 15/23] md/raid10 - support resizing some RAID10 arrays NeilBrown
2012-03-14 6:17 ` keld
2012-03-14 6:27 ` NeilBrown
2012-03-14 7:51 ` David Brown
2012-03-14 8:32 ` NeilBrown
2012-03-14 10:20 ` David Brown
2012-03-14 12:37 ` keld
2012-03-14 4:40 ` [md PATCH 18/23] md/bitmap: change a 'goto' to a normal 'if' construct NeilBrown
2012-03-14 4:40 ` [md PATCH 21/23] md/bitmap: discard CHUNK_BLOCK_SHIFT macro NeilBrown
2012-03-14 4:40 ` [md PATCH 17/23] md/bitmap: move printing of bitmap status to bitmap.c NeilBrown
2012-03-14 4:40 ` [md PATCH 19/23] md/bitmap: remove some pointless locking NeilBrown
2012-03-14 4:40 ` [md PATCH 23/23] md: Add judgement bb->unacked_exist in function md_ack_all_badblocks() NeilBrown
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