Playing with mdadm today I noticed it seems to allow full drive mirroring something I remember that raidtools would fail on. Back in raidtools days I remember that even though it was possible to mirror an entire drive with a single md volume (sda, sdb rather than sda1, sdb1) it really did not work and was not recommended. It looks like that is no longer the case with mdadm. Here is what I did. Took two hard drives and created a single partition that spans the whole drive. then do: mdadm --create --level=mirror --raid-devices=2 /dev/md1 /dev/sd[ab]1 Look using mdadm --detail and see Number Major Minor RaidDevice State 0 8 1 0 active sync /dev/sda1 1 8 17 1 active sync /dev/sdb1 I reboot and now using mdadm --detail I see: Number Major Minor RaidDevice State 0 8 0 0 active sync /dev/sda 1 8 16 1 active sync /dev/sdb So it would seem mdadm basically figured out what I wanted to do and no longer shows the partition number after a reboot. So next deleted all partitions on the drives and recreated the raid set without referencing the partitions mdadm --create --level=mirror --raid-devices=2 /dev/md1 /dev/sd[ab] That worked just fine and now mdadm --detail gives me the same as before (but without rebooting) Number Major Minor RaidDevice State 0 8 0 0 active sync /dev/sda 1 8 16 1 active sync /dev/sdb My questions are: Is there anything wrong with doing this as this was not recommend with raidtools. This with LVM or partition the md directly (cool feature you added) seems like a hard combo to beat? Does the MBR get synced across the drives when doing this? I know partition type does not seem to matter with mdadm compared to raidtools, but when creating partitions I use "da" rather than "fd", is that the recommended type or since it no longer seems to matter no one really cares what you use? I am using version mdadm - v2.6.7.2 - 14th November 2008 from Debian Lenny Thanks and I am pretty excited how mdadm keeps getting better and better. -- Jared > > -- Jared Raddigan Koinonia I.T. Director p. 916-577-7982 x101 http://www.kfh.org -- 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
