From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.galliera.it ([62.101.86.54]:32947 "EHLO smtp.galliera.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750940AbaIXO2i (ORCPT ); Wed, 24 Sep 2014 10:28:38 -0400 Received: from galliera.it (simoman.ceed [10.0.6.66]) by smtp.galliera.it (Postfix) with ESMTP id ED93330F755A for ; Wed, 24 Sep 2014 16:28:35 +0200 (CEST) Date: Wed, 24 Sep 2014 16:28:35 +0200 From: Simone Ferretti To: linux-btrfs@vger.kernel.org Subject: Re: mount problem Message-ID: <20140924142835.GA18272@galliera.it> References: <20140923120641.GA27624@galliera.it> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: linux-btrfs-owner@vger.kernel.org List-ID: Wed, Sep 24, 2014 at 01:23:32PM +0000, Duncan wrote: > Simone Ferretti posted on Tue, 23 Sep 2014 14:06:41 +0200 as excerpted: > > > we're testing BTRFS on our Debian server. After a lot of operations > > simulating a RAID1 failure, every time I mount my BTRFS RAID1 volume the > > kernel logs these messages: > > > > [73894.436173] BTRFS: bdev /dev/etherd/e30.20 errs: > > wr 33036, rd 0, flush 0, corrupt 2806, gen 0 > > [73894.436181] BTRFS: bdev /dev/etherd/e60.28 errs: > > wr 244165, rd 0, flush 0, corrupt 1, gen 4 > > > > Everything seems to work nice but I'm courious to know what these > > messages mean (in particular what do "gen" and "corrupt" mean?). > > Gen=generation. The generation or transaction-ID (different names for > the exact same thing) is a monotonically increasing integer that gets > updated every time a tree update reaches all the way to the superblock. > In the error context, it means the superblock had one generation number > but N other blocks had a different (presumably older) generation number. > > Corrupt is simply the number of blocks where the calculated checksum > didn't match the recorded checksum, thus indicating an error. > > See btrfs device stats -z to reset the numbers to zero (after printing > them one last time). Thank you much for your quick and illuminating answer. I'm wondering if you (or anyone else of course) know if there is btrfs documentation/papers/anything (besides wiki I did not find anything), in which it's possible to learn this kind of informations? -- Bye, Simone