From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: mdadm, bitmap and split-brain Date: Tue, 6 Dec 2011 15:45:22 +1100 Message-ID: <20111206154522.13235bf4@notabene.brown> References: <4ED14BEF.2060301@gmail.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/5yY3A0_/TC3azfEhJl0CuQc"; protocol="application/pgp-signature" Return-path: In-Reply-To: <4ED14BEF.2060301@gmail.com> Sender: linux-raid-owner@vger.kernel.org To: Ronal Andadinata Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids --Sig_/5yY3A0_/TC3azfEhJl0CuQc Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Sun, 27 Nov 2011 03:28:31 +0700 Ronal Andadinata wrote: > Hi, >=20 > I'm wondering, in the case of raid1 array with internal bitmap, it goes=20 > like this : > 1. Machine A has 1 raid1 array with Disk1 dan Disk2 > 2. Dettach Disk2 from Machine A, put it on Machine B > 3. Machine A runs normally, Machine B runs on normally on different place. > 4. Detach Disk2 from Machine B, put it back on Machine A, re-add Disk2=20 > to md1 >=20 > If this were raid1 without bitmap, Disk2 will be overwritten from=20 > scratch with contents of Disk1, what happen if the array has bitmap ?=20 > Would there be partial sync ? Would the two disk be identical with only=20 > using partial sync ? It might fail to re-add, or it might do a partial resync and probably leave the two devices different so corruption would likely appear. Just don't do this. If you want to use disk2 on a different machine, assemble it with=20 --update=3Duuid the first time so it gets a different uuid and can never become confused wi= th the old array. NeilBrown --Sig_/5yY3A0_/TC3azfEhJl0CuQc Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) iQIVAwUBTt2d4jnsnt1WYoG5AQKGFRAAkNDvi4L4UY4OLjz5WgKFnDAsKBwDRIw+ Cl4+nlU5bm8WbEADIKSUyXhfSG3ZiFlB9264dPKUvRP9nglMomxBqziK9bXB0ORf Z+kCc0XDlMqLGpPUdvf5Bz0tCgrDbYS6I4bkz09vXRZVwij1iHSuJ31lcKrANV/u E1rlywlb9OWwD8v/iHxhflGBMzNzfxGdVaawOmimHY7IGmnD0hPZyAC3pmiVRxaZ CMiMNgzeF77bY4/Jrb6AWje7DQtUbj8LFmHKVgYSc/PD39avoDUib+xeUcylnT5d yEo/sYDXhHh9qWbBOTd3zdwDa7+y3Wj6BDUawH6lR0/QnxoYAd1iOK0YPYOByBzO /d9ypTtbpBDc7cc54uAFFu4cvFxGYO0PJjcndYYEgc1KApDCpf1EVAVMYaVIB9Yd qnmGFi2dOky8ryybW7+VLZbdE4Z5VY25CFuynGqHX1iJ/vdFOphgwZ2R6eOA5O8l LXAicnaUVw2QD8A1ZFAh71uTjoIMOiA+7tIfgPwaIQWBKao4D3cMKm0/e+HYtXtY wUL/9OnqW/cDL5BTsiATk3QUj4vp+0nPBpp/HHsyYvbEqmbFSTEoDc+LK5borx3V A3PHi30IPgLU5aVepxvH/9mszfV6bTtzRKmPA8S8cDPv0gdJLDBNR7p1vUkyi1Zk ri08jgtWKDs= =jzdj -----END PGP SIGNATURE----- --Sig_/5yY3A0_/TC3azfEhJl0CuQc--