Comment # 25 on bug 832501 from Andrei Borzenkov

(In reply to Marco M. from comment #23)
> I was unable to boot with a degraded raid 1 array (both boot and root where
> on raid)
> 

I cannot reproduce this using boot on MD RAID with current Factory. Your log
shows

[  143.781288] linux-m61d dracut-initqueue[270]: Warning: Cancelling resume
operation. Device not found.
[  144.094926] linux-m61d systemd[1]: Timed out waiting for device
dev-disk-by\x2duuid-1f3d0926\x2da660\x2d45a6\x2da2b0\x2dbfdf165d64b5.device.
[  144.096300] linux-m61d systemd[1]: Dependency failed for /sysroot.
[  144.098235] linux-m61d systemd[1]: Dependency failed for Initrd Root File
System.
[  144.099596] linux-m61d systemd[1]: Dependency failed for Reload
Configuration from the Real Root.
[  144.100150] linux-m61d systemd[1]: Dependency failed for File System Check
on /dev/disk/by-uuid/1f3d0926-a660-45a6-a2b0-bfdf165d64b5.
[  144.553192] linux-m61d dracut-initqueue[270]: Scanning devices md2  for LVM
logical volumes SystemVG/rootLV

So it is actually problem of LVM on RAID, not RAID itself.

/dev/mapper/SystemVG-rootLV: LABEL="rootFS"
UUID="1f3d0926-a660-45a6-a2b0-bfdf165d64b5" TYPE="ext4"

Please provide your initrd that fails as already requested.