212 lines
5.6 KiB
ReStructuredText
212 lines
5.6 KiB
ReStructuredText
.. highlight:: sh
|
|
|
|
Recovery
|
|
======================
|
|
|
|
.. contents:: Table of Contents
|
|
:local:
|
|
|
|
GRUB Tips
|
|
-------------
|
|
|
|
Boot from GRUB rescue
|
|
~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
If bootloader file is damaged, it's still possible
|
|
to boot computer with GRUB rescue image.
|
|
|
|
This section is also applicable if you are in
|
|
``grub rescue>``.
|
|
|
|
#. On another computer, generate rescue image with::
|
|
|
|
pacman -S --needed mtools libisoburn grub
|
|
grub-install
|
|
grub-mkrescue -o grub-rescue.img
|
|
dd if=grub-rescue.img of=/dev/your-usb-stick
|
|
|
|
Boot computer from the rescue media.
|
|
Both legacy and EFI mode are supported.
|
|
|
|
Or `download generated GRUB rescue image <https://nu8.org/pages/projects/bieaz/#grub-rescue-images>`__.
|
|
|
|
#. List available disks with ``ls`` command::
|
|
|
|
grub> ls (hd # press tab
|
|
Possible devices are:
|
|
|
|
hd0 hd1 hd2 hd3
|
|
|
|
#. List partitions by pressing tab key:
|
|
|
|
.. code-block:: text
|
|
|
|
grub> ls (hd0 # press tab
|
|
Possible partitions are:
|
|
|
|
Device hd0: No known filesystem detected - Sector size 512B - Total size 20971520KiB
|
|
Partition hd0,gpt1: Filesystem type fat - Label `EFI', UUID 0DF5-3A76 - Partition start at 1024KiB - Total size 1048576KiB
|
|
Partition hd0,gpt2: No known filesystem detected - Partition start at 1049600KiB - Total size 4194304KiB
|
|
|
|
- If boot pool is encrypted:
|
|
|
|
Unlock it with ``cryptomount``::
|
|
|
|
grub> insmod luks
|
|
grub> cryptomount hd0,gpt2
|
|
Attempting to decrypt master key...
|
|
Enter passphrase for hd0,gpt2 (af5a240e13e24483acf02600d61e0f36):
|
|
Slot 1 opened
|
|
|
|
Unlocked LUKS container is ``(crypto0)``:
|
|
|
|
.. code-block:: text
|
|
|
|
grub> ls (crypto0)
|
|
Device crypto0: Filesystem type zfs - Label `bpool_ip3tdb' - Last modification
|
|
time 2021-05-03 12:14:08 Monday, UUID f14d7bdf89fe21fb - Sector size 512B -
|
|
Total size 4192256KiB
|
|
|
|
- If boot pool is not encrypted:
|
|
|
|
.. code-block:: text
|
|
|
|
grub> ls (hd0,gpt2)
|
|
Device hd0,gpt2: Filesystem type zfs - Label `bpool_ip3tdb' - Last modification
|
|
time 2021-05-03 12:14:08 Monday, UUID f14d7bdf89fe21fb - Sector size 512B -
|
|
Total size 4192256KiB
|
|
|
|
#. List boot environments nested inside ``bpool/$INST_ID/BOOT``::
|
|
|
|
grub> ls (crypto0)/sys/BOOT
|
|
@/ default/ be0/
|
|
|
|
#. Instruct GRUB to load configuration from ``be0`` boot environment::
|
|
|
|
grub> prefix=(crypto0)/sys/BOOT/be0/@/grub
|
|
grub> configfile $prefix/grub.cfg
|
|
|
|
#. GRUB menu should now appear.
|
|
|
|
#. After entering system, `reinstall GRUB <#grub-installation>`__.
|
|
|
|
Switch GRUB prefix when disk fails
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
If you are using LUKS encrypted boot pool with multiple disks,
|
|
the primary disk failed, GRUB will fail to load configuration.
|
|
|
|
If there's still enough redundancy for the boot pool, try fix
|
|
GRUB with the following method:
|
|
|
|
#. Ensure ``Slot 1 opened`` message
|
|
is shown
|
|
|
|
.. code-block:: text
|
|
|
|
Welcome to GRUB!
|
|
|
|
error: no such cryptodisk found.
|
|
Attempting to decrypt master key...
|
|
Enter passphrase for hd0,gpt2 (c0987ea1a51049e9b3056622804de62a):
|
|
Slot 1 opened
|
|
error: disk `cryptouuid/47ed1b7eb0014bc9a70aede3d8714faf' not found.
|
|
Entering rescue mode...
|
|
grub rescue>
|
|
|
|
If ``error: access denied.`` is shown,
|
|
try re-enter password with::
|
|
|
|
grub rescue> cryptomount hd0,gpt2
|
|
|
|
#. Check prefix::
|
|
|
|
grub rescue > set
|
|
# prefix=(cryptouuid/47ed1b7eb0014bc9a70aede3d8714faf)/sys/BOOT/be0@/grub
|
|
# root=cryptouuid/47ed1b7eb0014bc9a70aede3d8714faf
|
|
|
|
#. Set correct ``prefix`` and ``root`` by replacing
|
|
``cryptouuid/UUID`` with ``crypto0``::
|
|
|
|
grub rescue> prefix=(crypto0)/sys/BOOT/default@/grub
|
|
grub rescue> root=crypto0
|
|
|
|
#. Boot GRUB::
|
|
|
|
grub rescue> insmod normal
|
|
grub rescue> normal
|
|
|
|
GRUB should then boot normally.
|
|
|
|
#. After entering system, edit ``/etc/fstab`` to promote
|
|
one backup to ``/boot/efi``.
|
|
|
|
#. Make the change to ``prefix`` and ``root``
|
|
permanent by `reinstalling GRUB <#grub-installation>`__.
|
|
|
|
Access system in chroot
|
|
-----------------------
|
|
|
|
#. Go through `preparation <1-preparation.html>`__.
|
|
|
|
#. Import and unlock root and boot pool::
|
|
|
|
zpool import -NR /mnt rpool_$INST_UUID
|
|
zpool import -NR /mnt bpool_$INST_UUID
|
|
|
|
If using password::
|
|
|
|
zfs load-key rpool_$INST_UUID/$INST_ID
|
|
|
|
If using keyfile::
|
|
|
|
zfs load-key -L file:///path/to/keyfile rpool_$INST_UUID/$INST_ID
|
|
|
|
#. Find the current boot environment::
|
|
|
|
zfs list
|
|
BE=default
|
|
|
|
#. Mount root filesystem::
|
|
|
|
zfs mount rpool_$INST_UUID/$INST_ID/ROOT/$BE
|
|
|
|
#. chroot into the system::
|
|
|
|
arch-chroot /mnt /bin/bash --login
|
|
zfs mount -a
|
|
mount -a
|
|
|
|
#. Finish rescue. See `finish installation <5-bootloader.html#finish-installation>`__.
|
|
|
|
Backup and migrate existing installation
|
|
----------------------------------------
|
|
With the help of `zfs send
|
|
<https://openzfs.github.io/openzfs-docs/man/8/zfs-send.8.html>`__
|
|
it is relatively easy to perform a system backup and migration.
|
|
|
|
#. Create a snapshot of root file system::
|
|
|
|
zfs snapshot -r rpool/arch@backup
|
|
zfs snapshot -r bpool/arch@backup
|
|
|
|
#. Save snapshot to a file or pipe to SSH::
|
|
|
|
zfs send --options rpool/arch@backup > /backup/arch-rpool
|
|
zfs send --options bpool/arch@backup > /backup/arch-bpool
|
|
|
|
#. Re-create partitions and root/boot
|
|
pool on target system.
|
|
|
|
#. Restore backup::
|
|
|
|
zfs recv rpool_new/arch < /backup/arch-rpool
|
|
zfs recv bpool_new/arch < /backup/arch-bpool
|
|
|
|
#. Chroot and reinstall bootloader.
|
|
|
|
#. Update pool name in ``/etc/fstab``, ``/boot/grub/grub.cfg``
|
|
and ``/etc/zfs/zfs-list.cache/*``.
|
|
|
|
#. Update device name, etc, in ``/etc/fstab`` and ``/etc/crypttab``.
|