From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from frost.carfax.org.uk ([85.119.82.111]:49468 "EHLO frost.carfax.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755385AbbJHVNy (ORCPT ); Thu, 8 Oct 2015 17:13:54 -0400 Date: Thu, 8 Oct 2015 21:13:52 +0000 From: Hugo Mills To: Austin S Hemmelgarn Cc: Pavel Pisa , linux-btrfs@vger.kernel.org Subject: Re: BTRFS RAID1 behavior after one drive temporal disconection Message-ID: <20151008211352.GC25907@carfax.org.uk> References: <201510052226.47051.pisa@cmp.felk.cvut.cz> <201510081028.02178.pisa@cmp.felk.cvut.cz> <561657D5.1070809@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="3y/CVJp2vtgPOhvS" In-Reply-To: <561657D5.1070809@gmail.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: --3y/CVJp2vtgPOhvS Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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 --3y/CVJp2vtgPOhvS Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJWFtyPAAoJEFheFHXiqx3k2ScP/RIV4HDChKBjgOCGxQHZl4IA 2SspqucXcnAtB91ZpcKX0xa5TUla1Q/SVr4OIlnRp0HmOzf3ksl8vkf7qMSuc2Oa Uhx3JIhWImsxrMDqUH1CuSjQj/i2CUsAK56gVgTeMwlWW3X1bAL6TA39OqSLn/rh q/RxEhmE/0guz3uv7FGnkYIe4oyn21wmm6Lazjm1PDIh6DZm88pw53PujsAbZ05f BEktqLHmydePQT0j2JAQ1QJkrNCOnkKnpnZwqkY8ADlRN04g9Xn5SLouv+xf4mkf 1hp4oFZSi4y8xD+XPTynqjdfTZ2j7BQSqN4uO4Q2cDE7PTOPzpYuNkmG9F9iZ/xg CZ9xM+Mschcdg+nJA1yXvzc4SR6IgUUH2lX/LcucjccG9PMcJLhbypeO0/fgFOZU meTuITTmX6KZ/1EWWQn6WVVjnTSKTYVJVFIWbBJYQ0V4KEQzPq2xWCSpE3BA1UBR ALE1b6ef3+O4YwG58fVBGyonXHt3iTtaozHW8iWDLN6XX+Q5u9Vy6R0ibletPAGY to9W9p7EwFTfSWrpVxhFn4aQzw7dzMDcfmMRA2UXfHFigAgY1uHgdg3c32m7SHka KhjCu0dJSs/tweZzjSMH7D6Kp8PffhNoplW8uQz/D3oMSKl7ScH3R4xHrmI1Ff9J Tg5EEG9UnvCda3GKCVKg =SeM4 -----END PGP SIGNATURE----- --3y/CVJp2vtgPOhvS--