On Thu, 25 Aug 2011 19:13:59 -0700 Dan Williams <dan.j.williams@xxxxxxxxx> wrote: > I run imsm raid5 and raid1 arrays on my personal systems and was > recently bit by the bug that was fixed in commit 1a2487c2 "FIX: imsm: > OROM does not recognize degraded arrays (V2)". In the process of > investigating that I pulled the wrong disk and ended up in a dual > degraded situation. > > These patches (ordered in roughly increasing order of required review) > are the features needed to get the array up and running again, as well > as some random fixes spotted along the way. > > The most important patch for recovery being patch7 "imsm: support > 'missing' devices at Create", allowing the mdadm raid5 recovery path of > recreating the raid array with what one thinks are the good disks / > order, and then attempt to mount the filesystem to see if the guess was > correct. > > Example, create degraded raid5 with slot1 missing. > > mdadm --create /dev/md0 /dev/sd[ac] -n 2 -e imsm > mdadm --create /dev/md1 /dev/sda missing /dev/sdc -n 3 -l 5 > > However, during this process I wanted to make sure I could get back to > the exact same metadata that was on the disks, to root cause what went > wrong, examine the metadata offline, or backup a step if I made a > mistake in the recovery process. Patch9 implements --dump support, the > fact that something like this has not been implemented already is maybe > a clue that it is not such a great idea? I can imagine someone messing > up their configuration if they restored a metadata image to the wrong > device, but if you know what you are doing it could be a useful hack. > > --- > > Dan Williams (9): > imsm: fix max disks per array > imsm: fix, stop metadata updates to newly failed devices > imsm: fix display spares > sysfs: fix sysfs_disk_to_scsi_id > imsm: fix reserved sectors for spares > mdmon: fix, close spare activation race > imsm: support 'missing' devices at Create > util: allow regular files through test_partition() > mdadm: 'dump' support > > > Examine.c | 42 ++++++++++++++++ > ReadMe.c | 1 > managemon.c | 5 ++ > mdadm.8.in | 13 +++++ > mdadm.c | 11 ++++ > mdadm.h | 3 + > super-intel.c | 146 +++++++++++++++++++++++++++++++++++++-------------------- > sysfs.c | 30 ++++-------- > util.c | 6 ++ > 9 files changed, 182 insertions(+), 75 deletions(-) Thanks. I've applied all but the last two - which I might want done slightly differently as discussed already. I also fixed a build breakage in "make everything" .... though maybe I should get rid of mdassemble - it is hard to maintain and I'm not really sure that it is useful. Thanks, NeilBrown -- 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
