Re: How to Boot with LVM
ray a écrit :
> I would like to configure LVMs for everything including boot. I have
> read that others have done this but an I have not found the method.
> System description:
> amd64 with a HDD and 3 pairs of SSDs. The SSD are set up as RAID0 in
> pairs. The HDD currently hosts Debian 8. I used this to configure the
> SSDs to overlay the RAID0s with an LVM. The RAIDs were built on a
> second partition of each SSD. The first partition is 1G for potential
> boot use.
LVM on multiple RAID0 ? You don't care much about reliability, do you ?
Lose a single disk and you may lose all your LVM.
> I use a USB stick to load the second Debian. I have a lVM partition
> for the new installation. When I select it, the installer (in manual
> mode) says it is not bootable and go back to setup to correct. When I
> go back to setup, I don't see any way to do anything but select a VG,
> dm, sdx, or HDD.
I assume the architecture is i386 or amd64.
If /boot is on LVM and you choose GRUB as the bootloader in BIOS/legacy
mode (grub-pc), you must select a whole disk.
If the disk has an MSDOS partition table, it should have enough
unallocated space before the first partition ; modern partition
management tools including the Debian installer will leave ~1 MB
unallocated space by default, which is enough.
If the disk has a GPT partition table, it should contain a small
unformatted partition of type "BIOS boot" or "bios_grub" ; again, 1 MB
is enough. If the disk is larger than 2 TiB, the BIOS boot partition
should be located within the 2 TiB boundary so that it can be accessed
through the BIOS disk functions.
The unallocated space or BIOS boot partition is required to install the
GRUB's core image which can be booted by the GRUB's boot image installed
in the MBR of the disk. The core image will include modules to be able
to read RAID and LVM volumes in order to access other required boot
files located in /boot. Otherwise, GRUB's core image will be installed
in /boot/grub and retrieved by GRUB's boot image using block lists ;
however this is less reliable because blocks may be moved around by LVM
or the filesystem.