> Hi, > > Nicolas Courtel wrote on 2009-04-30 11:11:46 +0200 [Re: setup-storage for > raid5 + lvm]: > > > > >># mdadm --zero-superblock /dev/sda2 > > >># /lib/udev/vol_id -u /dev/sda2 > > >>6428a2d1-c30d-4916-ab6b-625117989651 > > >>[...] > > > > > >Ok, good to know, thanks for testing this. I wonder whether we should do > > >something about this in setup-storage, but I believe that doing mdadm > > >--zero-superblock on each and every non-RAID device is pure overkill. > > > > I agree. You may want to add a few words in the error message, > > something like "Failed to obtain UUID [...], check that $device_name is > > not or has not been a RAID partition". >
Finally done (and included in 3.2.21+experimental6): The code in question now reads 99 # every device must have a uuid, otherwise this is an error (unless we 100 # are testing only) 101 ($FAI::no_dry_run == 0 || scalar (@uuid) == 1) 102 or die "Failed to obtain UUID for $device_name.\n 103 This may happen if the device was part of a RAID array in the past;\n 104 in this case run mdadm --zero-superblock $device_name and retry\n"; > sorry, I'm not familiar with the code in question, so I don't know if it's > actually possible, but ideally, detecting this failure would trigger possible > remedies to the problem (eg. zeroing the RAID superblock - unless this is > potentially harmful for reasons not obvious to me right now) and then re-try. > I can imagine that this might not be as simple to implement as it sounds. > > As an alternative, there could be a "pedantic mode" (triggered by some flag) > which actually does zero each potential superblock (again, unless there is > some reason this might be undesirable). Then, if you hit trouble with a > particular installation, you could simply turn on this flag and see if it > solves your problem without needing to go into any extensive debugging. Having > something that "just works" even in awkward circumstances without manual > intervention does not seem like a bad idea, does it? Thinking about the > complexity of a modern Linux system, though, I tend to agree that something > like that should be turned off by default ;-). > I do love to do as much automagically as possible, but in that case I'd rather not go for it: Exit code 4 of vol_id -u may occur in several cases, so better let the user do it themselves. I hope the error message provides enough information such that the user knows what do to and the mdadm stuff is probably as easy as restarting setup-storage in pedantic mode (if there were such a thing). Best, Michael
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