From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from frost.carfax.org.uk ([85.119.82.111]:59151 "EHLO frost.carfax.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759451Ab3GRWDO (ORCPT ); Thu, 18 Jul 2013 18:03:14 -0400 Date: Thu, 18 Jul 2013 23:03:09 +0100 From: Hugo Mills To: Roger Binns Cc: linux-btrfs@vger.kernel.org Subject: Re: Questions about multi-device behavior Message-ID: <20130718220309.GD20517@carfax.org.uk> References: <1860433.azE0Vf7tMy@horus> <20130718173337.GN24343@twin.jikos.cz> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="4zI0WCX1RcnW9Hbu" In-Reply-To: Sender: linux-btrfs-owner@vger.kernel.org List-ID: --4zI0WCX1RcnW9Hbu Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Thu, Jul 18, 2013 at 02:59:58PM -0700, Roger Binns wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > On 18/07/13 13:05, Chris Murphy wrote: > > Sounds like if I have a degraded 'single' volume, I can simply cp or > > rsync everything from that volume to another, and I'll end up with a > > successful copy of the surviving data. True? > > Not quite. I did it with cp -a. Because all the metadata survived, cp > would create the target file, but then get an i/o error on opening/reading > the source file. It would print an error message, but not delete the > empty target file. Consequently I ended up with loads of zero length files > I had to go in and delete afterwards. The odds of having an undamaged file from that process are much better for single than for RAID-0 (and aren't affected by having tools which will cope better with IO errors -- although you'll get more of each damaged file if you do). As the file size goes up, the odds of it being damaged increase. Hugo. > I briefly looked for an rsync option to keep going on source i/o errors > but didn't find one. > > Roger > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.12 (GNU/Linux) > > iEYEARECAAYFAlHoZV4ACgkQmOOfHg372QRPFwCgob01TavS2qffBkxkuv0g9bl3 > pC8An25Mgx+cRXb0Kds+GRnzaj2P0Acy > =UA5J > -----END PGP SIGNATURE----- > -- === Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk === PGP key: 65E74AC0 from wwwkeys.eu.pgp.net or http://www.carfax.org.uk --- I am an opera lover from planet Zog. Take me to your lieder. --- --4zI0WCX1RcnW9Hbu Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIVAwUBUehmHVheFHXiqx3kAQIRDQ//RI+KpcVaC8aE09719aXeum9NHyMpLPHB LlFf1lQjfnZUbhrf1/64qxu+0DrOw3CzLOL/eznnPxzAVMTTPmbg1dGlse/8cFBZ U6nrrnusgPJAyB8sjBBmceN6PZpNFvzsrN6WC3eIAsDsSKJ41AFydnLHr054MfRk iE6fGebxDKvPZK8BeJ5ruhRut0r+2DepMnZ/gClIfxvbWRp6QJrRHmosQzmdu3d9 329twi/zELQGnzFevkrXh/vEtZpn9qaYirMyDeU/BJR7oeoNTFGsYPMKZiRcw7uD ACqhHTznNEGNVgotHaIFrwkisD6mkD/g4J4GdD0Pe8vheNkdTm00r8z/EjEAQ1JW uUMAdOQ9y5J42vCI7xaYhKNvGXzXuxBIYxgSPn9uDxkahXa6jnUkPYgBf5lQVfE8 btg1NAOBRDFPrgjUBnzfjPzrvxuxZm1cuK3254IbFNjy9kjN1TDI1Q6qnl8CN6M9 nhfW4xKk0ePypq82WAGn6u7f/6SgKP1Y6gjzjEffd8l/7FbqubPh4BEGg5+4L+OK 2gMwqWNlZ8/sEO8nB7TJ7EH74DP5jqvAwnN2qDpn7j6J2klXMzYkuroKT1AiSiVL kKuNYOExCIhJa7Z5HyKSRU1Oor0jEPG4CtQ8RlB4VqLzNexvqiUlyPqGEPsHzBpE e9l/ioz/I9I= =CuP4 -----END PGP SIGNATURE----- --4zI0WCX1RcnW9Hbu--