On Friday 07 May 2010 08:22:00 deloptes wrote: > Jozsi Vadkan wrote: > > Did anyone managed to boot from RAID1? > > > > Lenny gives this error message: > > > > "mdadm: no devices found for /dev/md0" > >
> You'll need a small i.e. 20-30MB partition out of raid to boot from with > i.e. initrd which loads the md driver and your raid device becomes visible. Just for the record, it actually *is* possible to boot off a partition that's in RAID1, but you might have to use grub. The reason it works is because grub can read past the md-raid1 metadata without getting confused -- since the raid is not running when grub is looking at the disks, it only sees one of the two, but since they're mirrored, and since grub doesn't *write* to the partition, everything works. I have several production systems that do this. It's a bit complicated to set up, but generally, it goes something like: - Install a basic system onto one drive, with the correct size of partition (call this /dev/sda1). - Set up an "incomplete" RAID1 array, with one device and one missing, with the second drive -- this is /dev/md0, consisting of /dev/sdb1 and an empty slot. - Configure /etc/mdadm/mdadm.conf, and re-build your initramfs so that it has the md modules and knows about the array. - Mount /dev/md0 somewhere and copy all the data off /dev/sda1 to it. It's very important to get the *new* initramfs onto the array. - Install grub in the bootloader of the 2nd drive. (The installer already did this for the first one). This actually isn't essential, but you may need it if/when /dev/sda fails. - Boot on to the incomplete RAID array -- root=/dev/md0. - Add /dev/sda1 to the array, and sync. Now you have a bootable software raid-1 system. I'm not saying this solves the OP's problem, necessarily, but it's perfectly possible. I've never tried it with LILO or grub2, but I would think it would work. -- A. -- Andrew Reid / rei...@bellatlantic.net -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/201005071303.20994.rei...@bellatlantic.net