= Move root and boot to new LVM mirrored SDDs =

== LVM ==
Detail see [https://wiki.gentoo.org/wiki/LVM]

=== Basic Discs ===
two 1TB disks. Partition layout will be gpt with 3 partitions (BIOS boot 2M, EFI system, Linux LVM).
LVM will be RAID1.
Disks are sdd and sde on initial attachment.

==== Partitioning: ==== 
{{{
fdisk /dev/sdd
g
n default +2M
t 1 4
n default +128M
t 2 1
n default default
t 3 30
w
p
}}}
Result:
{{{
Festplatte /dev/sdd: 931,51 GiB, 1000204886016 Bytes, 1953525168 Sektoren
Festplattenmodell: Samsung SSD 870 
Einheiten: Sektoren von 1 * 512 = 512 Bytes
Sektorgröße (logisch/physikalisch): 512 Bytes / 512 Bytes
E/A-Größe (minimal/optimal): 512 Bytes / 512 Bytes
Festplattenbezeichnungstyp: gpt
Festplattenbezeichner: EA219CEB-45F9-C34C-8C6B-A3F491EA8B88

Gerät      Anfang       Ende   Sektoren  Größe Typ
/dev/sdd1    2048       6143       4096     2M BIOS boot
/dev/sdd2    6144     268287     262144   128M EFI-System
/dev/sdd3  268288 1953525134 1953256847 931,4G Linux LVM
}}}
repeat for second disk /dev/sde

==== LVM: ==== 
===== Physical volumes =====
{{{
pvcreate /dev/sd[de]3
}}}
Result in **dvdisplay**
{{{
  --- Physical volume ---
  PV Name               /dev/sdd3
  VG Name               vg01
  PV Size               <931,39 GiB / not usable 2,69 MiB
  Allocatable           yes 
  PE Size               4,00 MiB
  Total PE              238434
  Free PE               172897
  Allocated PE          65537
  PV UUID               9KCwX5-KuDX-de30-J0ke-9822-ljkX-wj3jKr
   
  --- Physical volume ---
  PV Name               /dev/sde3
  VG Name               vg01
  PV Size               <931,39 GiB / not usable 2,69 MiB
  Allocatable           yes 
  PE Size               4,00 MiB
  Total PE              238434
  Free PE               172897
  Allocated PE          65537
  PV UUID               N4TuOc-Dq6A-ZwVW-61t7-gfME-pSFu-Q9Iwty
}}}
===== Volume group =====
{{{
vgcreate vg01 /dev/sd[de]3
}}}
Result in **vgdisplay**
{{{
  --- Volume group ---
  VG Name               vg01
  System ID             
  Format                lvm2
  Metadata Areas        2
  Metadata Sequence No  4
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                1
  Open LV               1
  Max PV                0
  Cur PV                2
  Act PV                2
  VG Size               <1,82 TiB
  PE Size               4,00 MiB
  Total PE              476868
  Alloc PE / Size       131074 / <512,01 GiB
  Free  PE / Size       345794 / <1,32 TiB
  VG UUID               i1M7O9-dbOQ-azV4-ajmF-utwq-cKaj-RhBROV
}}}
===== Logical Volumes =====
====== for root ======
{{{
lvcreate --mirrors 1 --type raid1 -L 256G -n root vg01
}}}
Result in **lvdisplay**
{{{
  --- Logical volume ---
  LV Path                /dev/vg01/root
  LV Name                root
  VG Name                vg01
  LV UUID                N95R5k-dFV6-VecO-j2yQ-nQ12-xjwC-eyjnZ9
  LV Write Access        read/write
  LV Creation host, time snailix, 2021-11-11 23:58:06 +0100
  LV Status              available
  # open                 1
  LV Size                256,00 GiB
  Current LE             65536
  Mirrored volumes       2
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           252:4
}}}

=== block ids ===
==== root ====
{{{
blkid | grep vg01-root
}}}
{{{
/dev/mapper/vg01-root_rimage_0: UUID="06a2c8e7-dc77-49db-8e72-c7d0fa9ebe77" BLOCK_SIZE="4096" TYPE="ext4"
/dev/mapper/vg01-root: UUID="06a2c8e7-dc77-49db-8e72-c7d0fa9ebe77" BLOCK_SIZE="4096" TYPE="ext4"
/dev/mapper/vg01-root_rimage_1: UUID="06a2c8e7-dc77-49db-8e72-c7d0fa9ebe77" BLOCK_SIZE="4096" TYPE="ext4"
}}}
==== boot ====
{{{
blkid | grep sdd2
}}}
{{{
/dev/sdd2: UUID="bfb2c0c7-e7bf-44d3-b8c9-1cd60ace50a4" BLOCK_SIZE="1024" TYPE="ext2" PARTUUID="e7666b15-77f8-2942-806b-6f5a198fa496"
}}}

=== copy root from old installation ===
Boot from USB and mount the old and the new root. mount using UUID to be sure to mount the right devices.
{{{
mkdir /mnt/root-old
mkdir /mnt/root-new
mount UUID="fcafeec5-6c23-4edd-acf3-dfab41ae7776" /mnt/root-old
mount UUID="06a2c8e7-dc77-49db-8e72-c7d0fa9ebe77" /mnt/root-new
rsync -aHv --progress --delete /mnt/root-old/ /mnt/root-new/
}}}

=== fstab ===
edit fstab to reflect the UUIDs
{{{
UUID="bfb2c0c7-e7bf-44d3-b8c9-1cd60ace50a4"     /boot           ext2            noauto,noatime          1 2
UUID="06a2c8e7-dc77-49db-8e72-c7d0fa9ebe77"     /               ext4            noatime                 0 1
...
}}}

=== initramfs ===
mount sdd2 on boot (using UUID to be sure that it is the correct one)
{{{
umount /boot
mount UUID="bfb2c0c7-e7bf-44d3-b8c9-1cd60ace50a4" /boot
}}}
generate initrd (wiht lvm busybox luks support)
{{{
genkernel --lvm --busybox --luks --install initramfs
}}}

=== grub2 ===
Grub2 installation. using gpt layout but no UEFI.
==== Install ====
{{{
grub-install /dev/sdd
grub-install /dev/sde
}}}
==== Default ====
in /etc/default/grub
{{{
GRUB_CMDLINE_LINUX="dolvm root=UUID=06a2c8e7-dc77-49db-8e72-c7d0fa9ebe77 rootfstype=ext4 vga=0x31B init=/usr/lib/systemd/systemd"
}}}
==== Config ====
{{{
grub-mkconfig -o /boot/grub/grub.cfg
}}}
**Remark:** for me during runtime the disks are sdd (hd3) and sde (hd4) but during boot they are sda (hd0) and sdb (hd1) because the devices on the hardware controller are moved to sda, ...
Therfore I have to change the hd-entries in /boot/grub/grub.cfg using
{{{
sed -i 's/hd3/hd0/g' /boot/grub/grub.cfg
}}}
==== Sync boot over discs ====
to be able to boot from another disk (I have 3 disk that have a grub2 installation) I use the following script. (create mountpoints in /mnt accordingly). And this relies on a correct entry for boot in fstab)
{{{
echo 'mount boot'
mount /boot
echo 'mount sda1'
mount /dev/sda1 /mnt/sda1
echo 'mount sde2'
mount /dev/sde2 /mnt/sde2
echo 'sync to sda1'
rsync -aHv --progress --delete /boot/ /mnt/sda1/
echo 'sync to sde2'
rsync -aHv --progress --delete /boot/ /mnt/sde2/
echo 'umount sde2'
umount /mnt/sde2
echo 'umount sda1'
umount /mnt/sda1
echo 'umount boot'
umount /boot
echo 'done'
}}}