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From: Marc MERLIN <marc@merlins.org>
To: linux-btrfs@vger.kernel.org
Subject: btrfs raid5 recovery with >1 half failed drive, or multiple drives kicked out at the same time.
Date: Sat, 17 Aug 2013 08:46:27 -0700	[thread overview]
Message-ID: <20130817154627.GG12805@merlins.org> (raw)

I know the raid5 code is still new and being worked on, but I was
curious.

With md raid5, I can do this:
mdadm /dev/md7 --replace /dev/sde1

This is cool because it lets you replace a drive with bad sectors where
at least one other drive in the array has bad sectors, and the md layer
will read all drives for each stripe and write to a new drive.
The nice part is that it'll take the working parts of each drive, and as
long as no 2 drives have an unreadable sector for the same stripe, it
can recover.

I was curious, how does btrfs handle this situation, and more generally
drive failures, spurious multiple drive failures due to a bus blip where
you force the drives back online, and so forth?

Thanks,
Marc
-- 
"A mouse is a device used to point at the xterm you want to type in" - A.S.R.
Microsoft is to operating systems ....
                                      .... what McDonalds is to gourmet cooking
Home page: http://marc.merlins.org/

                 reply	other threads:[~2013-08-17 16:05 UTC|newest]

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