Re: BTRFS RAID1 behavior after one drive temporal disconection

[Hugo Mills <hugo@carfax.org.uk>]

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On Thu, Oct 08, 2015 at 07:47:33AM -0400, Austin S Hemmelgarn wrote:
> On 2015-10-08 04:28, Pavel Pisa wrote:
> >I go to use "btrfs replace" because there has not been any reply to my inplace correction
> >question. But I expect that clarification if possible/how to resync RAID1 after one
> >drive temporal disappear is really important to many of BTRFS users.
> As of right now, there is no way that I know of to safely re-sync a
> drive that's been disconnected for a while.  The best bet is
> probably to use replace, but for that to work reliably, you would
> need to tell it to ignore the now stale drive when trying to read
> each chunk.

   Scrub is officially what you need there. I can confirm that it
works correctly, having used it myself after accidentally unplugging
the wrong drive.

   Hugo.

(Sorry for the delay, I wrote this earlier, but had trouble sending it)

> It is theoretically possible to wipe the FS signature on the out-of
> sync drive, run a device scan, then run 'replace missing' pointing
> at the now 'blank' device, although going that route is really
> risky.
> 



-- 
Hugo Mills             | Gomez, darling, don't torture yourself.
hugo@... carfax.org.uk | That's my job.
http://carfax.org.uk/  |
PGP: E2AB1DE4          |                                       Morticia Addams

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