Installing on GPT LVM

This is updated version of this Howto Setting up LVM on GPT-labeled disks.

This document describes how to set up a system booting from a logical volume in Alpine using lvm2 and GPT-labeled disks.

Begin by booting from Alpine installation media in the usual way. Log in as `root`, run `setup-alpine`, and answer `none` when asked to choose a disk.

Info

Alpinelinux ISO used in this installation: alpine-2.7.2-x86.iso

This PC have BIOS and not UEFI(uefi installation may differ)

Tested on ALIX.3D3 with CF from 8GB.

Partitioning

We need to install some tools, as 'gptfdisk' is now part of main we do not need to add @edge/testing repository, but need to add one more mirror just in case mirror did not sync: Firstly we need to add second mirror to /etc/apk/repositories

vi /etc/apk/repositories

@edge http://nl.alpinelinux.org/alpine/edge/main

Now we can install it

apk add -U gptfdisk@edge

Create some partition. In my case disk is found as sda, so I will use it in whole process.

gdisk /dev/sda

# create a new empty GUID partition table (GPT) with 'o'
o # then 'y' to confirm
# create some partition: BIOS (needed only for GRUB2), Boot (needed by SYSLINUX), and rest LVM
n
1
<enter>
+2M
ef02
n
2
<enter>
+100M
8300
n
3
<enter>
<enter>
8e00
# print the partition table with 'p'

You should get something like this:

Number  Start (sector)    End (sector)  Size       Code  Name
  1            2048            6143   2.0 MiB     EF02  BIOS boot partition
  2            6144          210943   100.0 MiB   8300  Linux filesystem
  3          210944        15662270   7.4 GiB     8E00  Linux LVM

We need to set the 'legacy BIOS bootable' flag on our boot partition, which can be done in gdisk by first entering expert mode with 'x' and then edit attributes with 'a'. It's used by SYSLINUX's GPT support to identify a partition that holds second-stage boot code.

x
a
2
2

It looks like this:

Command (? for help): x

Expert command (? for help): a
Partition number (1-3): 2
Known attributes are:
0: system partition
1: hide from EFI
2: legacy BIOS bootable
60: read-only
62: hidden
63: do not automount

Attribute value is 0000000000000000. Set fields are:
 No fields set

Toggle which attribute field (0-63, 64 or <Enter> to exit): 2
Have enabled the 'legacy BIOS bootable' attribute.
Attribute value is 0000000000000004. Set fields are:
2 (legacy BIOS bootable)

Write table to disk with and exit gdisk with 'w'.

You can verify the legacy_boot flag with sgdisk (also part of the gptfdisk)

sgdisk /dev/sda --attributes=1:show

sgdisk /dev/sda --attributes=2:show

2:2:1 (legacy BIOS bootable)

sgdisk /dev/sda --attributes=3:show

Remove gptfdisk

apk del gptfdisk

LVM Setup

Now we can setup LVM on the third partition created in above process.

apk add lvm2 e2fsprogs syslinux

pvcreate /dev/sda3

 Physical volume "/dev/sda3" successfully created

vgcreate vg0 /dev/sda3

 Volume group "vg0" successfully created

lvcreate -n alpine.rootfs -L 1G vg0

 Logical volume "alpine.rootfs" created

lvcreate -n swap -C y -L 512M vg0

 Logical volume "swap" created

rc-update add lvm

* service lvm added to runlevel default

vgchange -ay

 2 logical volume(s) in volume group "vg0" now active

Format new logical volume and activate swap

mkfs.ext3 /dev/sda2

mkfs.ext4 /dev/vg0/alpine.rootfs

mkswap /dev/vg0/swap

Mount for finishing alpinelinux installation.

mount -t ext4 /dev/vg0/alpine.rootfs /mnt

mkdir /mnt/boot

mount -t ext3 /dev/sda2 /mnt/boot

Finish installation

Run this command to finish installing alpinelinux to our newly mounted partition on /mnt

setup-disk -m sys /mnt

Output of setup-disk should be like this

Installing system on /dev/vg0/alpine.rootfs:
/mnt/boot is device /dev/sda2
/boot is device /dev/sda2
You might need fix the MBR to be able to boot

Syslinux

Install the MBR:

dd bs=440 conv=notrunc count=1 if=/usr/share/syslinux/gptmbr.bin of=/dev/sda

Reboot and enjoy your new Alpine installation!