Synopis

I installed a new 1TB Crucial MX500 SSD into my work computer. While

we are mostly a Windows based business, as the IT guy I do get a bit of

discretion when updating my own machine (i.e. I get to solve all the

problems I create). Last year, I decided to run the Pop!_OS distribution

of Linux on my work computer and run Windows in a VM on it. Recently the

Windows image had grown and was causing disk space notifications. This

prompted the additional hard drive.

During the initial installation of Pop!_OS, I remember deciding not

to bother with installing Linux Volume Management (LVM). I have used it

in the past, but I am still much more comfortable with the old style

device mapping and mounting disk partitions to directories. I even

rationalized that if I needed to add more space, I will just add a new

disk with one big partition and map it to the home directory.

Now a year later I am adding a new HD and thinking, I really hate all

the space that is most likely going to be wasted once I move the Windows

image to the new drive. Ok, I guess I should figure out how to install

LVM, and use it to manage the space on both drives. Luckily there a

number of good blogs to be found on adding LVM to an existing system.

The following are the steps and commands I used to accomplish my

goal.

Commands

Most of the following commands need to be run as root. I decided to

change to root user instead of typing sudo before every command. The

basic steps to creating a single filesystem sharing the storage space

between two physical disk partitions are:

Let LVM know about the new disk.

In my case, create a volume group and add the new disk and its full

storage space to it.

Copy the disk partition with the root filesystem from the origin

disk to the new volume group

Expand the root filesystem on the volume group to the full size of

the volume group.

Update system configuration to boot with the root filesystem on the

new volume group.

Let LVM know about the old root disk partition.

Add the old root partition to the volume group.

Expand the root filesystem on the volume group to include the new

space in the volume group.

root@work# pvcreate /dev/sdb

root@work# pvdisplay

"/dev/sdb" is a new physical volume of "931.51 GiB"

--- NEW Physical volume ---

PV Name /dev/sdb

VG Name

PV Size 931.51 GiB

Allocatable NO

PE Size 0

Total PE 0

Free PE 0

Allocated PE 0

PV UUID wRBz38-xxxx-xxxx-xxxx-xxxx-xxxx-xxxxxx

root@work# vgcreate workvg /dev/dsb

No device found for /dev/dsb.

root@work# vgcreate workvg /dev/sdb

Volume group "workvg" successfully created

root@work# vgdisplay

--- Volume group ---

VG Name workvg

System ID

Format lvm2

Metadata Areas 1

Metadata Sequence No 1

VG Access read/write

VG Status resizable

MAX LV 0

Cur LV 0

Open LV 0

Max PV 0

Cur PV 1

Act PV 1

VG Size 931.51 GiB

PE Size 4.00 MiB

Total PE 238467

Alloc PE / Size 0 / 0

Free PE / Size 238467 / 931.51 GiB

VG UUID 67DSwP-xxxx-xxxx-xxxx-xxxx-xxxx-xxxxxx

root@work# pvdisplay

--- Physical volume ---

PV Name /dev/sdb

VG Name workvg

PV Size 931.51 GiB / not usable 1.71 MiB

Allocatable yes

PE Size 4.00 MiB

Total PE 238467

Free PE 238467

Allocated PE 0

PV UUID wRBz38-xxxx-xxxx-xxxx-xxxx-xxxx-xxxxxx

root@work# lvcreate -n root -L 931.51 workvg

Rounding up size to full physical extent 9