On Tue, Oct 11, 2011 at 11:58:52PM +0200, Kurt Flex wrote: > > Hi, > > I've done a safe-upgrade today which upgraded grub: > > upgrade grub-pc 1.98+20100804-14 1.98+20100804-14+squeeze1 > > The same for grub-common. > > A dialog appeared which asked me to run grub-install. But that > failed. So i told the dialog to skip that part. Now I've tried > grub-install manually. > > # grub-install /dev/sda > /usr/sbin/grub-setup: warn: This msdos-style partition label has no > post-MBR gap; embedding won't be possible!. > /usr/sbin/grub-setup: error: embedding is not possible, but this is > required when the root device is on a RAID array or LVM volume. > > My google fu is not very good on this issue. > > # parted -l > Model: ATA WDC WD6400AACS-0 (scsi) > Disk /dev/sda: 640GB > Sector size (logical/physical): 512B/512B > Partition Table: msdos > > Number Start End Size Type File system Flags > 1 512B 100MB 100MB primary ext2 raid > 2 100MB 1124MB 1024MB primary linux-swap(v1) > 3 1124MB 610GB 609GB primary ext3 raid > > > Model: ATA WDC WD6400AACS-0 (scsi) > Disk /dev/sdb: 640GB > Sector size (logical/physical): 512B/512B > Partition Table: msdos > > Number Start End Size Type File system Flags > 1 512B 100MB 100MB primary ext2 raid > 2 100MB 1124MB 1024MB primary linux-swap(v1) > 3 1124MB 610GB 609GB primary ext3 raid > > > Model: Linux Software RAID Array (md) > Disk /dev/md0: 99.9MB > Sector size (logical/physical): 512B/512B > Partition Table: loop > > Number Start End Size File system Flags > 1 0.00B 99.9MB 99.9MB ext2 > > > Model: Linux Software RAID Array (md) > Disk /dev/md1: 609GB > Sector size (logical/physical): 512B/512B > Partition Table: loop > > Number Start End Size File system Flags > 1 0.00B 609GB 609GB ext3 > > > Any hints?
Looking at your partition table, you have 512 bytes between the start of the disk and your first partition. This is enough for a simple boot loader, but Grub uses a multi-stage boot system. The 512 byte "traditional" boot loader is termed "Stage 1". This jumps to "Stage 1.5" which is a larger section of code and which contains the drivers needed to load Stage 2. Stage 1.5, then would contain your MD driver and your EXT2 driver so that grub can read the contents of your file system and find /boot/grub/*. Stage 2 is then the full Grub, with the menu, the config file and so on. See http://en.wikipedia.org/wiki/GNU_GRUB#GRUB_version_1 for some useful info. Now, as you only have 512 bytes of 'free' space, Grub can't install its Stage 1.5 so is complaining. For a regular disk, it could probably perform a direct jump to Stage 2 and hope it doesn't move (it shouldn't), but as you have RAID, it can't do that. So, I think your options are to either shift your first parition up a little (30kb seems to be the usual recommendation) or to find a boot loader that IS capable of starting your RAID device in 512 bytes. -- Darac Marjal
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