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Re: How to Boot with LVM


Thank you for the informative response.  I would like to assure I address your concerns it this recovery.
> (...)
> > 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.  
sda, sdb 32GB + 32GB, RAID0 - md0, LVM, GParted shows 1MB reserved, 1 GB (EFI)
sdc, sdd 64GB + 64GB, RAID0- md1, md127, LVM, GParted shows 1MB reserved, 1 GB (EFI)
sde, sdf 120GB + 120GB, RAID0- md0, md126 LVM, GParted shows 1MB reserved, 1 GB (EFI)
sdg, sdh are 2 and 4 GB HD, sdg currently hosts debian8.+q++q
md0-2 form a vg for the new debian8 as dom0 for a xen instance, md127 is a vg, md126 is a vg.  md127 & 126 are for swap files.

> LVM on multiple RAID0 ? You don't care much about reliability, do you ?
> Lose a single disk and you may lose all your LVM.
Yes, there is risk.  This is a personal workstation and will be backed up regularly and doesn't need to be up all the time.  I have lost motherboards more often the disks, and I have never lost a ssd.  I chose Linux RAID over motherboard RAID due to this.

> > 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.
gdisk reports that the sda and sdb have gpt partitions.  > 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.

I have attempted again to install a new debian8 on the LVM on RAID0 for sda&b. I learned more about using the installer for portioning so I was able to get /boot on a RAID0 partition (outside of the vg).  

On rebooting, nothing would boot.  The screen message said to insert the media to boot from.  Now I get to recover what ever I lost.  I have not figured out how to do that.  Any help would be appreciated.

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