RAID 1 with one disk (for now)

aunquarra · 09-21-2007, 12:40 PM

I have an application where we need something done yesterday and it needs software RAID 1... Only problem is... One of the drives won't arrive until a couple weeks from now (one of the classic "fast/cheap/good; pick two" situations).

So, I'm wondering, is it possible for me to build a RAID 1 array with one of the disks missing, and then just have it catch up once it arrives? If so, how? If not, do you have any other suggestions?

acid_kewpie · 09-21-2007, 12:48 PM

it's possible yes...

Code:

linux:~ # mdadm --create /dev/md1 --level=1 --raid-devices=2 /dev/sdb1 missing
mdadm: array /dev/md1 started.

for example. now this is assuming that this is not for the core install, but an additional drive. if you needed to install into to a brand new degraded array, then if the installer for your distro doesn't let you, I am fairly confident that if you use any old live cd, probably including the install cd above, then you can manually create it a la the mdadm command above still, and any good installer should recognise it's existance during a normal install.