Assuming you can allow some downtime, get yourself a rescue CD such as 'RIP' This will let you boot into the machine and run mdadm commands. You don't mention kernel/mdadm versions so you may want to check they're close on the rescue CD. Then try looking at the manpage around --assemble. In particular you may want to try --scan and --uuid (if your RIP/live kernel/mdadm support it) Also check out the examples... Assuming this is a sane machine and you're not in real disaster recovery mode with drives pulled in from random boxes then look at using the literal string "--config=partitions" (see the manpage) to avoid creating an mdadm.conf with the "DEVICE partitions" line - PITA on live CDs where you just want a command line ;) If you can manage it, this will give you a nice warm feeling about recovering from a problem and it's pretty safe - just common sense like making sure the live CD kernel/mdadm are either up-to-date or match your production system. HTH Also: > I have thought about this, and I can't understand how 'mdadm' decides the > health of an array. Each disk/partition used by md has a superblock which contains a unique UUID and other info, like the number of devices and the raid level. mdadm --scan looks into each partition for a superblock and notes this data. It can then group all the superblocks with the same UUID together and, for each group, knowing how many devices it should have, how many it has and how many it needs it can decide if the device can safely be assembled. David PS Yes, I've done this (too many times!) - 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
