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80lvmmerge: README.md update

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Harald Hoyer 8 years ago
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1bfa75b015
  1. 8
      modules.d/80lvmmerge/README.md
  2. 47
      modules.d/80lvmmerge/lvmmerge.sh

8
modules.d/80lvmmerge/README.md

@ -1,7 +1,6 @@ @@ -1,7 +1,6 @@
# lvmmerge - dracut module

## Preparation

- ensure that the lvm thin pool is big enough
- backup any (most likely /boot and /boot/efi) device with:
```
@ -57,7 +56,6 @@ dracut will @@ -57,7 +56,6 @@ dracut will
- make a copy of the snapshot
- merge it back to the original
- rename the copy back to the name of the snapshot
- if /restordev appears in the root, then it will restore the images *.devimage
found in that directory. This can be used to restore /boot and /boot/efi.
Additionally any *.mbrimage files will be restored. This can be used
found in that directory. This can be used to restore /boot and /boot/efi
- if /restordev appears in the root, then it will restore the images
found in that directory. This can be used to restore /boot and /boot/efi and the
MBR of the boot device

47
modules.d/80lvmmerge/lvmmerge.sh

@ -1,52 +1,5 @@ @@ -1,52 +1,5 @@
#!/bin/bash

#
# How to prepare:
# - ensure that the lvm thin pool is big enough
# - backup any (most likely /boot and /boot/efi) device with:
# # mkdir /restoredev
# # dev=<device>; umount $dev; dd if="$dev" of=/restoredev/$(systemd-escape -p "$dev"); mount $dev
# - backup the MBR
# # dev=<device>; dd if="$dev" of=/restoredev/$(systemd-escape -p "$dev") bs=446 count=1
#
# # ls -l /dev/disk/by-path/virtio-pci-0000\:00\:07.0
# lrwxrwxrwx. 1 root root 9 Jul 24 04:27 /dev/disk/by-path/virtio-pci-0000:00:07.0 -> ../../vda
# # dev=/dev/disk/by-path/virtio-pci-0000:00:07.0
# # dd if="$dev" of=/restoredev/$(systemd-escape -p "$dev") bs=446 count=1
# # umount /boot/efi
# # dev=/dev/disk/by-partuuid/687177a8-86b3-4e37-a328-91d20db9563c
# # dd if="$dev" of=/restoredev/$(systemd-escape -p "$dev")
# # umount /boot
# # dev=/dev/disk/by-partuuid/4fdf99e9-4f28-4207-a26f-c76546824eaf
# # dd if="$dev" of=/restoredev/$(systemd-escape -p "$dev")
# # ls -al /restoredev/
# total 1253380
# drwx------. 2 root root 250 Jul 24 04:38 .
# dr-xr-xr-x. 18 root root 242 Jul 24 04:32 ..
# -rw-------. 1 root root 209715200 Jul 24 04:34 dev-disk-by\x2dpartuuid-4fdf99e9\x2d4f28\x2d4207\x2da26f\x2dc76546824eaf
# -rw-------. 1 root root 1073741824 Jul 24 04:34 dev-disk-by\x2dpartuuid-687177a8\x2d86b3\x2d4e37\x2da328\x2d91d20db9563c
# -rw-------. 1 root root 446 Jul 24 04:38 dev-disk-by\x2dpath-virtio\x2dpci\x2d0000:00:07.0
#
# - make a thin snapshot
# # lvm lvcreate -pr -s rhel/root --name reset
#
# - mark the snapshot with a tag
# # lvm lvchange --addtag reset rhel/reset
#
# - remove /restoredev
# # rm -fr /restoredev
#
# If a boot entry with rd.lvm.mergetags=<tag> is selected and there lv's with <tag>
# dracut will
# - make a copy of the snapshot
# - merge it back to the original
# - rename the copy back to the name of the snapshot
# - if /restordev appears in the root, then it will restore the images *.devimage
# found in that directory. This can be used to restore /boot and /boot/efi.
# Additionally any *.mbrimage files will be restored. This can be used
# found in that directory. This can be used to restore /boot and /boot/efi
#

type getarg >/dev/null 2>&1 || . /lib/dracut-lib.sh

do_merge() {

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