On Tue, Nov 4, 2014 at 1:06 AM, Michael Tokarev <mjt@xxxxxxxxxx> wrote: > > 01.11.2014 21:53, Stephen Kent wrote: > > I have set up a machine to use an md array as the root device. I have > > created the array with metadata type 1.2, name "root," on host > > "optimus" (so the full metadata name is "optimus:root"). > > > > I'm using Gentoo Linux (kernel 3.16.5-gentoo), and previously I had no > > initramfs so I wrote a short one to assemble the array. My initramfs > > sets the hostname and runs "mdadm -As," which correctly auto-assembles > > the root device array on /dev/md/root (even without an > > /etc/mdadm.conf). > > > > Once the initramfs script is finished, init starts which then starts > > udev. Now, at this point the array is already assembled, but the > > /dev/md/* name is lost (and so is /run/mdadm/map) since those files > > were on the initramfs' tempfs root. > > This is your problem. You should not lose neither /dev nor /run > when switching root. Usual thing to do is to mount tmpfs /dev and > tmpfs /run in initramfs and do mount --move /dev /root/dev (and > the same for /run) before switching root. > > Thanks, > > /mjt Hm, interesting. I didn't realize a mount point could be moved, that's good to know. My initramfs is a short custom shell script that I wrote, basically all it does is assemble the array and mount the root filesystem. I'm not mounting a tmpfs and/or udev on /run and /dev, so unfortunately there aren't any mount points to move to the target root mountpoint at the end of init. /run and /dev are only mounted on my machine after leaving the initramfs. Fortunately, NeilBrown's patch works for me which solves the problem and allows mdadm to work correctly with a minimal initramfs. Stephen -- 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
