On Tuesday, December 06, 2011 02:21:09 PM m.roth at 5-cent.us wrote: > Reindl Harald wrote: > > the device name is totally uninteresting, the IDs are > > mdadm /dev/mdx --add /dev/sdex > No, it's not uninteresting. I can't be sure that when it reboots, it won't > come back as /dev/sda. The RAIDsets will be assembled by UUID, not by device name. It doesn't matter whether it comes up as /dev/sda or /dev/sdah or whatever, except for booting purposes, which you'll need to handle manually by making sure all the bootloader sectors (some of which can be outside any partition) are properly copied over; just getting the MBR is not enough in some cases. I have, on upstream EL 6.1, a box with two 750G drives in RAID1 (they are not the boot drives). The device names for the component devices do not come up the same on every boot; some boots they come up as /dev/sdx and /dev/sdy, and some boots /dev/sdw and /dev/sdab, and others. The /dev/md devices come up fine and get mounted fine even though the component device names are somewhat nondeterministic.