From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adam Ryczkowski Subject: mdadm kernel log messages explained Date: Sun, 16 Sep 2012 11:01:41 +0200 Message-ID: <50559575.4090806@statystyka.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Welcome. I try to recover from linux software raid failure. I am in a process of recreating the superblocks based on a syslog from the system when it was healthy. The log speaks about 2 md devices, each based on 5 500GB partitions. The RAID-5 /dev/md5 is composed from /dev/sd[b-f]6 and RAID-6 /dev/md6 is composed from /dev/sd[b-f]5. The relevant part dmesg log looks like this: Questions: # What do the numbers on the line [ 5.979771] 4: w=1 pa=0 pr=5 m=1 a=2 r=5 op1=0 op2=0 mean, including the first 4:? # What do the numbers on the line [ 6.039266] --- rd:5 wd:5] mean? # What do the numbers on the line [ 6.046856] disk 0, o:1, dev:sdb6 mean? # Does the line [ 6.096768] created bitmap (15 pages) for device md5 tell anything about the place, where the bitmap is located and what is its size? The messages are produced by the 2.6.32 kernel, Ubuntu Lucid. (This mail is a copy of serverfault question (http://serverfault.com/questions/427692/mdadm-kernel-log-messages-explained) which I guess didn't get to the right audience) [ 5.964928] raid5: allocated 5265kB for md5 [ 5.979771] 4: w=1 pa=0 pr=5 m=1 a=2 r=5 op1=0 op2=0 [ 5.987064] 1: w=2 pa=0 pr=5 m=1 a=2 r=5 op1=0 op2=0 [ 5.994256] 3: w=3 pa=0 pr=5 m=1 a=2 r=5 op1=0 op2=0 [ 6.001441] 2: w=4 pa=0 pr=5 m=1 a=2 r=5 op1=0 op2=0 [ 6.008665] 0: w=5 pa=0 pr=5 m=1 a=2 r=5 op1=0 op2=0 [ 6.015883] raid5: raid level 5 set md5 active with 5 out of 5 devices, algorithm 2 [ 6.031441] RAID5 conf printout: [ 6.039266] --- rd:5 wd:5 [ 6.046856] disk 0, o:1, dev:sdb6 [ 6.054308] disk 1, o:1, dev:sdf6 [ 6.061524] disk 2, o:1, dev:sdc6 [ 6.068667] disk 3, o:1, dev:sde6 [ 6.075774] disk 4, o:1, dev:sdd6 [ 6.089504] md5: bitmap initialized from disk: read 1/1 pages, set 0 bits [ 6.096768] created bitmap (15 pages) for device md5 [ 6.141010] md5: detected capacity change from 0 to 1978409418752 [ 6.153794] md5: unknown partition table [ 5.594614] raid5: device sde5 operational as raid disk 3 [ 5.599701] raid5: device sdd5 operational as raid disk 4 [ 5.604750] raid5: device sdf5 operational as raid disk 1 [ 5.609879] raid5: device sdc5 operational as raid disk 2 [ 5.615032] raid5: device sdb5 operational as raid disk 0 [ 5.621672] raid5: allocated 5265kB for md6 [ 5.627243] 3: w=1 pa=0 pr=5 m=2 a=2 r=5 op1=0 op2=0 [ 5.632846] 4: w=2 pa=0 pr=5 m=2 a=2 r=5 op1=0 op2=0 [ 5.638502] 1: w=3 pa=0 pr=5 m=2 a=2 r=5 op1=0 op2=0 [ 5.644155] 2: w=4 pa=0 pr=5 m=2 a=2 r=5 op1=0 op2=0 [ 5.649844] 0: w=5 pa=0 pr=5 m=2 a=2 r=5 op1=0 op2=0 [ 5.655566] raid5: raid level 6 set md6 active with 5 out of 5 devices, algorithm 2 [ 5.667653] RAID5 conf printout: [ 5.673791] --- rd:5 wd:5 [ 5.679837] disk 0, o:1, dev:sdb5 [ 5.685721] disk 1, o:1, dev:sdf5 [ 5.691570] disk 2, o:1, dev:sdc5 [ 5.697348] disk 3, o:1, dev:sde5 [ 5.703122] disk 4, o:1, dev:sdd5 [ 5.710762] md6: bitmap initialized from disk: read 1/1 pages, set 0 bits [ 5.716915] created bitmap (15 pages) for device md6 -- Adam Ryczkowski Skype:sisteczko