Hi All, I was wondering if someone might be willing to confirm what the current state of my RAID array is, given the following sequence of events (sorry it's pretty long).... I had a clean, running /dev/md0 using 5 disks in RAID 5 (sda1, sdb1, sdc1, sdd1, hdd1). It had been clean like that for a while. So last night I decided it was safe to grow the array into a sixth disk.... [root@space ~]# mdadm /dev/md0 --add /dev/hdi1 mdadm: added /dev/hdi1 [root@space ~]# mdadm -D /dev/md0 /dev/md0: Version : 00.90.03 Creation Time : Wed Jan 9 18:57:53 2008 Raid Level : raid5 Array Size : 1953535744 (1863.04 GiB 2000.42 GB) Used Dev Size : 488383936 (465.76 GiB 500.11 GB) Raid Devices : 5 Total Devices : 6 Preferred Minor : 0 Persistence : Superblock is persistent Update Time : Tue Feb 5 23:55:59 2008 State : clean Active Devices : 5 Working Devices : 6 Failed Devices : 0 Spare Devices : 1 Layout : left-symmetric Chunk Size : 64K UUID : 382c157a:405e0640:c30f9e9e:888a5e63 Events : 0.429616 Number Major Minor RaidDevice State 0 8 1 0 active sync /dev/sda1 1 8 17 1 active sync /dev/sdb1 2 8 33 2 active sync /dev/sdc1 3 22 65 3 active sync /dev/hdd1 4 8 49 4 active sync /dev/sdd1 5 56 1 - spare /dev/hdi1 [root@space ~]# mdadm --grow /dev/md0 --raid-devices=6 mdadm: Need to backup 1280K of critical section.. mdadm: ... critical section passed. [root@space ~]# cat /proc/mdstat Personalities : [raid6] [raid5] [raid4] md0 : active raid5 hdi1[5] sdd1[4] sdc1[2] sdb1[1] sda1[0] hdd1[3] 1953535744 blocks super 0.91 level 5, 64k chunk, algorithm 2 [6/6] [UUUUUU] [>....................] reshape = 0.0% (29184/488383936) finish=2787.4min speed=2918K/sec unused devices: <none> [root@space ~]# OK, so that would take nearly 2 days to complete, so I went to bed happy about 10 hours ago. I come to the machine this morning, and I have the following.... [root@space ~]# cat /proc/mdstat Personalities : [raid6] [raid5] [raid4] md0 : active raid5 hdi1[5] sdd1[6](F) sdc1[2] sdb1[1] sda1[0] hdd1[3] 1953535744 blocks super 0.91 level 5, 64k chunk, algorithm 2 [6/5] [UUUU_U] unused devices: <none> You have new mail in /var/spool/mail/root [root@space ~]# mdadm -D /dev/md0 /dev/md0: Version : 00.91.03 Creation Time : Wed Jan 9 18:57:53 2008 Raid Level : raid5 Array Size : 1953535744 (1863.04 GiB 2000.42 GB) Used Dev Size : 488383936 (465.76 GiB 500.11 GB) Raid Devices : 6 Total Devices : 6 Preferred Minor : 0 Persistence : Superblock is persistent Update Time : Wed Feb 6 05:28:09 2008 State : clean, degraded Active Devices : 5 Working Devices : 5 Failed Devices : 1 Spare Devices : 0 Layout : left-symmetric Chunk Size : 64K Delta Devices : 1, (5->6) UUID : 382c157a:405e0640:c30f9e9e:888a5e63 Events : 0.470964 Number Major Minor RaidDevice State 0 8 1 0 active sync /dev/sda1 1 8 17 1 active sync /dev/sdb1 2 8 33 2 active sync /dev/sdc1 3 22 65 3 active sync /dev/hdd1 4 0 0 4 removed 5 56 1 5 active sync /dev/hdi1 6 8 49 - faulty spare [root@space ~]# df -k Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/VolGroup00-LogVol00 56086828 11219432 41972344 22% / /dev/hda1 101086 18281 77586 20% /boot /dev/md0 1922882096 1775670344 69070324 97% /Downloads tmpfs 513556 0 513556 0% /dev/shm [root@space ~]# mdadm /dev/md0 --remove /dev/sdd1 mdadm: cannot find /dev/sdd1: No such file or directory [root@space ~]# As you can see, one of the original 5 devices has failed (sdd1) and automatically removed. The reshape has stopped, but the new disk seems to be in and clean which is the bit I don't understand. The new disk hasn't been added to the size, so it would seem that md has switched it to being used as a spare instead (possibly as the grow hadn't completed?). How come it seems to have recovered so nicely? Is there something I can do to check it's integrity? Was it just so much quicker than 2 days because it switched to only having to sort out the 1 disk? Would it be safe to run an fsck to check the integrity of the fs? I don't want to inadvertently blat the raid array by 'using' it when it's in a dodgy state. I have unmounted the drive for the time being, so that it doesn't get any writes until I know what state it is really in. Any suggestions gratefully received, Steve. No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.19.20/1261 - Release Date: 05/02/2008 20:57 - 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