Hi, First of all, I would like to thank falko for his very comprehensive "How To Set Up Software RAID1 On A Running System"-HowTo. It was exactly what I needed. That said, I do have a question I hope he (or anyone else for that matter) can answer. Everything works fine, when I boot the system my two 160Gb HDDs are running nicely in RAID1. At boot-up, I get this grub boot menu: Code: Debian GNU/Linux, kernel 2.6.18-6-686 (RAID, hd1) Debian GNU/Linux, kernel 2.6.18-6-686 (RAID, hd0) I have it setup so that it times out waiting for user input after 5 seconds after which it boots my system. All is well - or so it seems. When I manually choose the first option (boot from hd1) I get this error message: Code: Booting 'Debian GNU/Linux, kernel 2.6.18-6-686 (hd1)' root (hd1,0) Filesystem type is ext2fs, partition type 0x83 kernel /boot/vmlinuz-2.6.18-6-686 root=/dev/md0 ro Error 15: File not found Press any key to continue... When I manually choose the second option (boot from hd0), it boots fine. This is my menu.lst (to preserve space, I omitted the unimportant bits - mostly comments. Also, I highlighted a few things I thought might be important): Code: # menu.lst default 0 fallback 1 timeout 5 color cyan/blue white/blue # kopt=root=[b]/dev/md0[/b] ro # groot=([b]hd1[/b],0) # alternative=true # lockalternative=false # defoptions= # lockold=false # xenhopt= # xenkopt=console=tty0 # altoptions=(single-user mode) single # howmany=all # memtest86=true # updatedefaultentry=false ## ## End Default Options ## title Debian GNU/Linux, kernel 2.6.18-6-686 (RAID, hd1) root (hd1,0) kernel /boot/vmlinuz-2.6.18-6-686 root=/dev/md0 ro initrd /boot/initrd.img-2.6.18-6-686 savedefault title Debian GNU/Linux, kernel 2.6.18-6-686 (RAID, hd0) root (hd0,0) kernel /boot/vmlinuz-2.6.18-6-686 root=/dev/md0 ro initrd /boot/initrd.img-2.6.18-6-686 savedefault Examining /proc/mdstat shows the RAID is running fine: Code: ~# cat /proc/mdstat Personalities : [raid1] md5 : active raid1 sda9 sdb9 144882048 blocks [2/2] [UU] md4 : active raid1 sda8 sdb8 1003904 blocks [2/2] [UU] md3 : active raid1 sda7 sdb7 2008000 blocks [2/2] [UU] md2 : active raid1 sda6 sdb6 10008384 blocks [2/2] [UU] md1 : active raid1 sda5 sdb5 979840 blocks [2/2] [UU] md0 : active raid1 sda1 sdb1 1951744 blocks [2/2] [UU] unused devices: <none> I have no idea why it throws the "Error 15" when I try to boot from hd1. They (hd0 & hd1) should be each other's mirror, so a file found on one should be found on the other, right? So does anybody know what's going on? Thanks in advance!