So I have a system (a large instance running ubuntu-11.10 on Amazon EC2) where I've done something like
mdadm --create bigdata --level 0 --raid-devices=2 /dev/xvdb /dev/xvdc
I get a RAID device of two disks (ephemeral instance stores) at
/dev/md/bigdata. Yay. reboot. I now have a RAID device of two disks at
ip-10-811-498-737:bigdata. (ip anonymized).
This is kind of obnoxious. I'd like to set up the RAID in a user-data install script, and set it up with a known device name, and then mount things from
/etc/fstab - but the device name changes between creation and reboot, which makes this rather hard to pull off.
ip-10-811-498-737 is the hostname of the machine, and it seems to be the default for the
--homehost option, so I know where that's coming from -- I just don't know how to keep it from showing up on reboot. (It's also the only RAID array that these machines will ever be exposed to ever, for that matter.)