From: Dark Penguin <darkpenguin@yandex.ru>
To: Phil Turmel <philip@turmel.org>,
Edward Kuns <eddie.kuns@gmail.com>,
linux-raid@vger.kernel.org
Subject: Re: md failing mechanism
Date: Sat, 23 Jan 2016 13:33:39 +0300 [thread overview]
Message-ID: <56A35703.2020702@yandex.ru> (raw)
In-Reply-To: <56A2CA93.8020806@turmel.org>
>> I wonder what happens if the only drive in a degraded mirror fails?..
>
> Or any drive in a raid5 hits an error while replacing a failed disk.
>
> BOOM.
Oh... That sucks. I understand that BOOM would happen on a RAID-F, but
kicking the last drive doesn't seem like a very rational thing to do -
you would get a RAID with zero drives, which is not something anybody
would want in any situation!.. I thought it would get into some kind of
extreme panic mode so that you could at least save what you can...
Actually, it would make sense to avoid "BOOM" as much as possible;
instead of going into a "BOOM" mode, it should go into some kind of
"recovery" mode, when the array immediately turns read-only and allows
you to salvage as much data as you can from the faulty drive. It would
be especially useful in RAID5; only one faulty sector or even some other
stupid error without even faulty sectors should not cause total data
loss!.. I don't think it would be very hard to implement, or contradict
some important philosophy, but it would save data, jobs and lives. :)
Well, suppose "BOOM" happened on my RAID1, and both drives failed.
Naturally, not at the same time, so data differs between the drives. So
I have two faulty drives; is it possible (with some other recovery
software?) to just mount each one read-only and copy data from it?.. I
can live with having to copy as much data as I can from the first one
and try to copy the rest from the older drive. I mean, I basically have
the entire filesystem there! I should be able to just mount the
filesystem on that drive, skipping the RAID header - just fdisk the
drive, delete the RAID partition and create another one starting a few
blocks later!.. Would that not work?.. That's actually why I chose
RAID1; even if everything goes BOOM, I should be able to mount the
drives separately!..
--
darkpenguin
next prev parent reply other threads:[~2016-01-23 10:33 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-22 17:59 md failing mechanism Dark Penguin
2016-01-22 19:29 ` Phil Turmel
2016-01-22 20:00 ` Wols Lists
2016-01-22 21:44 ` Dark Penguin
2016-01-22 22:18 ` Phil Turmel
2016-01-22 22:50 ` Dark Penguin
2016-01-22 23:23 ` Edward Kuns
2016-01-22 23:34 ` Wols Lists
2016-01-23 0:09 ` Dark Penguin
2016-01-22 22:37 ` Edward Kuns
2016-01-22 23:07 ` Dark Penguin
2016-01-22 23:39 ` Wols Lists
2016-01-23 0:09 ` Dark Penguin
2016-01-23 0:34 ` Phil Turmel
2016-01-23 10:33 ` Dark Penguin [this message]
2016-01-23 15:12 ` Phil Turmel
2016-01-22 23:40 ` James J
2016-01-23 0:44 ` Phil Turmel
2016-01-23 14:09 ` Wols Lists
2016-01-23 19:02 ` James J
2016-01-24 22:13 ` Adam Goryachev
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