From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from plane.gmane.org ([80.91.229.3]:40980 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753148AbaAVPjv (ORCPT ); Wed, 22 Jan 2014 10:39:51 -0500 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1W5zu9-0004A4-Uh for linux-btrfs@vger.kernel.org; Wed, 22 Jan 2014 16:39:49 +0100 Received: from ip68-231-22-224.ph.ph.cox.net ([68.231.22.224]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 22 Jan 2014 16:39:49 +0100 Received: from 1i5t5.duncan by ip68-231-22-224.ph.ph.cox.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 22 Jan 2014 16:39:49 +0100 To: linux-btrfs@vger.kernel.org From: Duncan <1i5t5.duncan@cox.net> Subject: Re: Scrubbing with BTRFS Raid 5 Date: Wed, 22 Jan 2014 15:39:27 +0000 (UTC) Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: Graham Fleming posted on Tue, 21 Jan 2014 10:03:26 -0800 as excerpted: > I want to keep playing around with BTRFSS RAID 5 and testing with it... > assuming I have a drive with bad blocks, or let's say some inconsistent > parity am I right in assuming that a) a btrfs scrub operation will not > fix the stripes with bad parity What I know is that it is said btrfs scrub doesn't work with btrfs raid5/6 yet. I don't know how it actually fails (tho I'd hope it simply returns an error to the effect that it doesn't work with raid5/6 yet) as I've not actually tried that mode, here. > and b) a balance operation will not be > successful? Or would a balance operation work to re-write parity? Balance actually rewrites everything (well, everything matching its filters if a filtered balance is used, everything, if not), so it should rewrite parity correctly. AFAIK, all the writing works and routine read works. It's the error recovery that's still only partially implemented. Since reading just reads data, not parity unless there's a dropped device or the like to recover from, as long as all devices are active and there's a good copy of the data (based on btrfs checksumming) to read, the rebalance should just use and rewrite that, ignoring the bad parity. -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman