From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jameson Graef Rollins Subject: Re: Bug#624343: linux-image-2.6.38-2-amd64: frequent message "bio too big device md0 (248 > 240)" in kern.log Date: Sun, 01 May 2011 15:06:45 -0700 Message-ID: <8739kyf53e.fsf@servo.factory.finestructure.net> References: <20110427161901.27049.31001.reportbug@servo.factory.finestructure.net> <1304051980.3105.46.camel@localhost> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" Return-path: In-Reply-To: <1304051980.3105.46.camel@localhost> Sender: linux-raid-owner@vger.kernel.org To: Ben Hutchings Cc: 624343@bugs.debian.org, NeilBrown , linux-raid@vger.kernel.org List-Id: linux-raid.ids --=-=-= Content-Transfer-Encoding: quoted-printable On Fri, 29 Apr 2011 05:39:40 +0100, Ben Hutchings wro= te: > On Wed, 2011-04-27 at 09:19 -0700, Jameson Graef Rollins wrote: > > I run what I imagine is a fairly unusual disk setup on my laptop, > > consisting of: > >=20 > > ssd -> raid1 -> dm-crypt -> lvm -> ext4 > >=20 > > I use the raid1 as a backup. The raid1 operates normally in degraded > > mode. For backups I then hot-add a usb hdd, let the raid1 sync, and > > then fail/remove the external hdd.=20 >=20 > Well, this is not expected to work. Possibly the hot-addition of a disk > with different bio restrictions should be rejected. But I'm not sure, > because it is safe to do that if there is no mounted filesystem or > stacking device on top of the RAID. Hi, Ben. Can you explain why this is not expected to work? Which part exactly is not expected to work and why? > I would recommend using filesystem-level backup (e.g. dirvish or > backuppc). Aside from this bug, if the SSD fails during a RAID resync > you will be left with an inconsistent and therefore useless 'backup'. I appreciate your recommendation, but it doesn't really have anything to do with this bug report. Unless I am doing something that is *expressly* not supposed to work, then it should work, and if it doesn't then it's either a bug or a documentation failure (ie. if this setup is not supposed to work then it should be clearly documented somewhere what exactly the problem is). > The block layer correctly returns an error after logging this message. > If it's due to a read operation, the error should be propagated up to > the application that tried to read. If it's due to a write operation, I > would expect the error to result in the RAID becoming desynchronised. > In some cases it might be propagated to the application that tried to > write. Can you say what is "correct" about the returned error? That's what I'm still not understanding. Why is there an error and what is it coming from? jamie. --=-=-= Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIcBAEBCAAGBQJNvdl1AAoJEO00zqvie6q8e7YP/0jerOnezmqjSi8S4CtYoerg S+R8vX23Lf1uRNpwcB4SXZa1U7COAsmQxaNpUFgf9dq1MD2e4HZxiSKGMIbfQi+K SkS+wH9ukuri76tHd8D7iGyiTKJfQHhv6qCi2nwcfJl4JhcntMX779cn92buFBKj JoogJT4C10S1P58T+qCQB0ZTenYbVnJNmVh19lnfdmDhn/FRAW/qbCZTh8s0rimU zF7yHz6EbXUi2LErks3M51X5bMRCpr2eYdJ7K6hVWBsCR8PLr+w4Da4sa63V0A4T tCk7a5t7fkRjbOgKrTUsoPwZDWlFQvFTmeZtxUxNCdybGa1OIiZKrwv1dnpokNVs KYODLM5RT697nmZeuiQ0k6wxSNimkEBWZan3sgapjWkOzqwzlbO3RVp5oXzlWeS4 6TZ3d5doKo/z7pm5z/dAgsD3VdfeEKvBL0ishFpLR09Mi9trkop2XnrpehsICzyn KKVWlcRgIzt+3KYmjtaa3EZPj/jekOAHZkuQIhyR27XXrR+6tg1fGSkIsOL+mhN8 gFUfeP4zahglzkDg2GH57P8tsgkZvZFTtAJF8QmBf9JlSQ0YqQmodNROcwjEnrcH k20F7H7SZxlsgkkqL51/cM1NgNRybTP9d0U4fZJTOsigmMEK19BW+fBgfuOdp4lO gG7VjFchx15qZ5m6so6T =7j5t -----END PGP SIGNATURE----- --=-=-=--