Migrate standard RHEL installation from one hard disk to another

Latest response

*** DON'T DO ANY OF THIS, AS YOU WILL ALMOST CERTAINLY WRECK YOUR SYSTEM IF YOU DO! ***

You have one standard installation of RHEL, you need migrate the installation from one hard disk to another, this is required due to technology improvement.

The server is productive and has running critical services, so is important minimize the migration window, this procedure requires only one reboot, if you want to apply all changes immediately but you can program the restart after.

For x86_64

Scenario:

vda -> Old Disk
vdb -> New Disk
centos -> root volume group

Partitioning:

# df -h
Filesystem               Size  Used Avail Use% Mounted on
/dev/mapper/centos-root   18G  983M   17G   6% /
devtmpfs                 487M     0  487M   0% /dev
tmpfs                    497M     0  497M   0% /dev/shm
tmpfs                    497M  6.7M  490M   2% /run
tmpfs                    497M     0  497M   0% /sys/fs/cgroup
/dev/vda1                497M  164M  333M  33% /boot
tmpfs                    100M     0  100M   0% /run/user/0
tmpfs                    100M     0  100M   0% /run/user/1000

# fdisk -l
   Device Boot      Start         End      Blocks   Id  System
/dev/vda1   *        2048     1026047      512000   83  Linux
/dev/vda2         1026048    41943039    20458496   8e  Linux LVM

Steps:

Clean yum cache:

# yum clean all

Clone partitioning scheme:

# sfdisk -d /dev/vda | sfdisk --force /dev/vdb

Move Logical Volume to new disk:

# pvcreate /dev/vdb2
# vgextend centos /dev/vdb2
# pvmove /dev/vda2
# vgreduce centos /dev/vda2
# pvremove /dev/vda2

Clone /boot:

# umount /boot/
# dd if=/dev/vda1 of=/dev/vdb1 bs=512 conv=noerror,sync
# mount /boot

Copy boot sector:

# dd if=/dev/vda of=/dev/vdb bs=1 count=512

Install GRUB in new disk:

# grub2-install /dev/vdb

Sync changes:

# sync

Reboot your physical or virtual machine, please make sure that your new disk is the default boot device or remove old disk but don't delete data, can be useful in a rollback situation.

For POWER
Scenario:

sda -> Old Disk
sdb -> New Disk
ca -> root volume group

Partitioning:

# df -h
Filesystem           Size  Used Avail Use% Mounted on
/dev/mapper/ca-root   28G  1.1G   27G   4% /
devtmpfs             449M     0  449M   0% /dev
tmpfs                495M     0  495M   0% /dev/shm
tmpfs                495M   12M  484M   3% /run
tmpfs                495M     0  495M   0% /sys/fs/cgroup
/dev/sda2            497M  143M  354M  29% /boot
tmpfs                 99M     0   99M   0% /run/user/0

# fdisk -l
  Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048       10239        4096   41  PPC PReP Boot
/dev/sda2           10240     1034239      512000   83  Linux
/dev/sda3         1034240    62914559    30940160   8e  Linux LVM

Steps:

Clean yum cache:

# yum clean all

Clone partitioning scheme:

# sfdisk -d /dev/sda | sfdisk --force /dev/sdb

Move Logical Volume to new disk:

# pvcreate /dev/sdb3
# vgextend centos /dev/sdb3
# pvmove /dev/sda3
# vgreduce centos /dev/sda3
# pvremove /dev/sda3

Clone PPC PReP Boot partition:

dd if=/dev/sda1 of=/dev/sdb1 bs=512 conv=noerror,sync

Clone /boot:

# umount /boot/
# dd if=/dev/sda2 of=/dev/sdb2 bs=512 conv=noerror,sync
# mount /boot

Copy boot sector:

# dd if=/dev/sda of=/dev/sdb bs=1 count=512

Install GRUB in new disk:

# grub2-install /dev/sdb

If you receive this message: grub2-install: error: the chosen partition is not a PReP partition. maybe you can try with:

# grub2-install /dev/sdb1

Sync changes:

# sync

Reboot your physical or virtual machine, please make sure that your new disk is the default boot device or remove old disk but don't delete data, can be useful in a rollback situation.

EM

Responses