From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from plane.gmane.org ([80.91.229.3]:37871 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754318AbaDKLXr (ORCPT ); Fri, 11 Apr 2014 07:23:47 -0400 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1WYZYd-0001dx-GC for linux-btrfs@vger.kernel.org; Fri, 11 Apr 2014 13:23:43 +0200 Received: from 78-32-127-104.static.enta.net ([78.32.127.104]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 11 Apr 2014 13:23:43 +0200 Received: from alex by 78-32-127-104.static.enta.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 11 Apr 2014 13:23:43 +0200 To: linux-btrfs@vger.kernel.org From: Alex Subject: What does scrub do? Date: Fri, 11 Apr 2014 11:23:31 +0000 (UTC) Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-btrfs-owner@vger.kernel.org List-ID: Hi all, Debian testing/Jessie-to-be; except kernels/btrfs-tools are from unstable so usually couple of weeks later than you/Linus publish. Linux XX 3.13-1-amd64 #1 SMP Debian 3.13.7-1 (2014-03-25) x86_64 Btrfs-tools v3.12 Debian standard (not particularly messed with looks like) I've never had scrub report anything other than 0 (zero) errors. Ever. Yet I've had more than one ( ;-) ) problem which required btrfs-zero-log and/or btrfs --repair. This are usually my fault - fixed it 'til it broke. root@XX ~ # btrfs scrub status / scrub status for f8152a67-3c2e-4da1-812e-9a6ab2ad1102 scrub started at Fri Apr 11 09:55:36 2014 and finished after 44 seconds total bytes scrubbed: 1.40GiB with 0 errors [ 7.502338] btrfs: device label china devid 1 transid 938773 /dev/vda1 [ 7.514213] btrfs: device label china devid 1 transid 938773 /dev/vda1 [ 7.530893] btrfs: disk space caching is enabled [ 7.530897] btrfs: has skinny extents [ 7.720288] btrfs: bdev /dev/vda1 errs: wr 0, rd 0, flush 0, corrupt 66, gen 2 [ 18.967319] btrfs: device label china devid 1 transid 938773 /dev/vda1 [ 19.360767] btrfs: device label china devid 1 transid 938773 /dev/vda1 This scrub and dmesg were taken within minutes of each other. So what it the utility of running scrub? Or have I got the the wrong idea of what scrub should report. This VM guest doesn't get messed with often, and is kept Very small KVM virtual machine - easy to send you a btrfs dump. Almost vanilla set-up too. Just say the word. Have been running btrfs here for quite some while (years, since Linux3.1 I think) on server. Very very stable (lzo compression sometimes not quite as stable as zlib and I only run it on the desktop m/c). People: for auto snapshots use Snapper (a la SUSE) which is now in Debian et al. Only peculiarity is that clear-down of daily snapshots only happens in the night so you don't need to put many/any hourly snapshots in. Thank you. And well done/thank you to the contributors. Al. PS: please get the 3.14 tools release out - perhaps the fixes have already gone through the tree and I am just shouting at the wind.