Dear all, I tried to convert my existing 5 disks RAID5 array to a 6 disks RAID6 array. This was my existing array: ---------------------------------------------------------------------------- ----------------------------------- /dev/md0: Version : 0.90 Raid Level : raid5 Array Size : 5860548608 (5589.05 GiB 6001.20 GB) Used Dev Size : 1465137152 (1397.26 GiB 1500.30 GB) Raid Devices : 5 Total Devices : 5 Persistence : Superblock is persistent State : clean Active Devices : 5 Working Devices : 5 Layout : left-symmetric Chunk Size : 512K Events : 0.156 Number Major Minor RaidDevice State 0 8 17 0 active sync /dev/sdb1 1 8 81 1 active sync /dev/sdf1 2 8 33 2 active sync /dev/sdc1 3 8 97 3 active sync /dev/sdg1 4 8 65 4 active sync /dev/sde1 ---------------------------------------------------------------------------- ------------------------------- I did the conversion according to "howtos", so: $ mdadm -add /dev/md0 /dev/sdd1 then: $ mdadm --grow /dev/md0 --level=6 --raid-devices=6 --backup-file=/mnt/mdadm-raid5-to-raid6.backup Instead of starting the reshape process, mdadm responded this: mdadm: /dev/md0: changed level to 6 (or something like that, i dont remember the exact words, but it was about changing the level). mdadm: /dev/md0: Cannot get array details from sysfs And the array became this: ---------------------------------------------------------------------------- ------------------------------- /dev/md0: Raid Level : raid6 Array Size : 5860548608 (5589.05 GiB 6001.20 GB) Used Dev Size : 1465137152 (1397.26 GiB 1500.30 GB) Raid Devices : 6 Total Devices : 6 Persistence : Superblock is persistent State : clean, degraded Active Devices : 5 Working Devices : 6 Failed Devices : 0 Spare Devices : 1 Events : 0.170 Number Major Minor RaidDevice State 0 8 17 0 active sync /dev/sdb1 1 8 81 1 active sync /dev/sdf1 2 8 33 2 active sync /dev/sdc1 3 8 97 3 active sync /dev/sdg1 4 8 65 4 active sync /dev/sde1 5 0 0 5 removed 6 8 49 - spare /dev/sdd1 ---------------------------------------------------------------------------- ------------------------------- At this point I realized that /dev/sdd previously was a member of another raid array in an other machine, and however I re-partitioned the disk, I didn't remove the old superblock. So maybe this was the reason for the mdadm error. Since the state of /dev/sdd1 was spare, i removed it: $ mdadm -remove /dev/md0 /dev/sdd1 then cleared remaining superblock $ mdadm --zero-superblock /dev/sdd1 then added it back to the array: mdadm --add /dev/md0 /dev/sdd1 and started the grow process again: $ mdadm --grow /dev/md0 --level=6 --raid-devices=6 --backup-file=/mnt/mdadm-raid5-to-raid6.backup mdadm: /dev/md0: no change requested Mdadm stated no change, however, it started to rebuild the array. It's currently rebuilding: ---------------------------------------------------------------------------- ------------------------------- /dev/md0: Version : 0.90 Raid Level : raid6 Array Size : 5860548608 (5589.05 GiB 6001.20 GB) Used Dev Size : 1465137152 (1397.26 GiB 1500.30 GB) Raid Devices : 6 Total Devices : 6 Persistence : Superblock is persistent State : clean, degraded, recovering Active Devices : 5 Working Devices : 6 Failed Devices : 0 Spare Devices : 1 Layout : left-symmetric-6 Chunk Size : 512K Rebuild Status : 2% complete Events : 0.186 Number Major Minor RaidDevice State 0 8 17 0 active sync /dev/sdb1 1 8 81 1 active sync /dev/sdf1 2 8 33 2 active sync /dev/sdc1 3 8 97 3 active sync /dev/sdg1 4 8 65 4 active sync /dev/sde1 6 8 49 5 spare rebuilding /dev/sdd1 ---------------------------------------------------------------------------- ------------------------------- Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active raid6 sdd1[6] sde1[4] sdc1[2] sdf1[1] sdg1[3] sdb1[0] 5860548608 blocks level 6, 512k chunk, algorithm 18 [6/5] [UUUUU_] [>....................] recovery = 2.3% (34438272/1465137152) finish=1074.5min speed=22190K/sec unused devices: <none> ---------------------------------------------------------------------------- ------------------------------- Mdadm didn't create the backup file, and the process seems too fast to me for a raid5->raid6 conversion. Please help me to understand what's happening now. Cheers, Peter -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
