On Wed, 01 Aug 2012 10:29:51 +0200 Albert Pauw <albert.pauw@xxxxxxxxx> wrote: > Hi Neil, > > here is a procedure which shows you another problem. It has to do with > the table produced at the end of the mdadm -E command, showing the disks > and their status. Seems when a disk has failed and another added, the > failed one disappears. > > Hope you can find the problem and fix it. > > Regards, > > Albert > > Here is the exact procedure which shows the problem: > > Create a container with 5 disks: > > mdadm -CR /dev/md127 -e ddf -l container -n 5 /dev/loop[1-5] > > Physical Disks : 5 > Number RefNo Size Device Type/State > 0 d1c8c16e 479232K /dev/loop1 Global-Spare/Online > 1 6de79cb6 479232K /dev/loop2 Global-Spare/Online > 2 b5fd1d6c 479232K /dev/loop3 Global-Spare/Online > 3 0be2d310 479232K /dev/loop4 Global-Spare/Online > 4 5d8ac3d0 479232K /dev/loop5 Global-Spare/Online > > > Create a RAID 5 set of 3 disks in container: > > mdadm -CR /dev/md0 -l 5 -n 3 /dev/md127 > > Physical Disks : 5 > Number RefNo Size Device Type/State > 0 d1c8c16e 479232K /dev/loop1 active/Online > 1 6de79cb6 479232K /dev/loop2 active/Online > 2 b5fd1d6c 479232K /dev/loop3 active/Online > 3 0be2d310 479232K /dev/loop4 Global-Spare/Online > 4 5d8ac3d0 479232K /dev/loop5 Global-Spare/Online > > > Create a RAID 1 set of 2 disks in container: > > mdadm -CR /dev/md1 -l 1 -n 2 /dev/md127 > > Physical Disks : 5 > Number RefNo Size Device Type/State > 0 d1c8c16e 479232K /dev/loop1 active/Online > 1 6de79cb6 479232K /dev/loop2 active/Online > 2 b5fd1d6c 479232K /dev/loop3 active/Online > 3 0be2d310 479232K /dev/loop4 active/Online > 4 5d8ac3d0 479232K /dev/loop5 active/Online > > > Fail first disk in RAID 5 set: > > mdadm -f /dev/md0 /dev/loop1 > > Physical Disks : 5 > Number RefNo Size Device Type/State > 0 d1c8c16e 479232K /dev/loop1 active/Offline, Failed > 1 6de79cb6 479232K /dev/loop2 active/Online > 2 b5fd1d6c 479232K /dev/loop3 active/Online > 3 0be2d310 479232K /dev/loop4 active/Online > 4 5d8ac3d0 479232K /dev/loop5 active/Online > > > Remove failed disk: > > mdadm -r /dev/md0 /dev/loop1 > > Physical Disks : 5 > Number RefNo Size Device Type/State > 0 d1c8c16e 479232K active/Offline, > Failed, Missing > 1 6de79cb6 479232K /dev/loop2 active/Online > 2 b5fd1d6c 479232K /dev/loop3 active/Online > 3 0be2d310 479232K /dev/loop4 active/Online > 4 5d8ac3d0 479232K /dev/loop5 active/Online > > > Add failed disk back: > > mdadm -a --force /dev/md0 /dev/loop1 > > Physical Disks : 5 > Number RefNo Size Device Type/State > 0 d1c8c16e 479232K /dev/loop1 active/Offline, > Failed, Missing > 1 6de79cb6 479232K /dev/loop2 active/Online > 2 b5fd1d6c 479232K /dev/loop3 active/Online > 3 0be2d310 479232K /dev/loop4 active/Online > 4 5d8ac3d0 479232K /dev/loop5 active/Online > > > Add spare disk to container: > > mdadm -a --force /dev/md0 /dev/loop6 > > Physical Disks : 5 > Number RefNo Size Device Type/State > 0 6de79cb6 479232K /dev/loop2 active/Online > 1 b5fd1d6c 479232K /dev/loop3 active/Online > 2 0be2d310 479232K /dev/loop4 active/Online > 3 5d8ac3d0 479232K /dev/loop5 active/Online > 4 1dcfe3cf 479232K /dev/loop6 active/Online, Rebuilding > > This is wrong! Physical disks should be 6 now! Whenever we add a device to the ddf we currently remove any record of any failed and missing device. We have to forget about devices that have disappeared at some stage, and this seems like a good place. The problem here is that a device that is in the array is marked as 'missing'. This due to the bug I mentioned in the previous email. Currently worked around by --zeroing the device before adding it. > > Removed failed disk (which is missing from list now!) again, zero > superblock and add again: > > mdadm -r /dev/md0 /dev/loop1 > mdadm --zero-superblock /dev/loop1 > mdadm -a --force /dev/md0 /dev/loop1 > > > Physical Disks : 6 > Number RefNo Size Device Type/State > 0 6de79cb6 479232K /dev/loop2 active/Online > 1 b5fd1d6c 479232K /dev/loop3 active/Online > 2 0be2d310 479232K /dev/loop4 active/Online > 3 5d8ac3d0 479232K /dev/loop5 active/Online > 4 1dcfe3cf 479232K /dev/loop6 active/Online > 5 8147a3ef 479232K /dev/loop1 Global-Spare/Online > > And there they are, all 6 of them. > NeilBrown
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