Adding new physical volume in encrypted volume group (LUKS)

Nikolaos Dimopoulos asked:

I have a CentOS 6.6 desktop and chose the encrypt option upon installation. This created a LUKS volume group. Everything works fine, but I want to add an additional drive to the volume group.

From reading and loads of googling I believe the process is to encrypt the drive first and then add it to the volume group.

--- Physical volume ---
PV Name               /dev/mapper/luks-9f2577eb-...
VG Name               vg_iridium
PV Size               931.51 GiB / not usable 2.00 MiB
Allocatable           yes (but full)
PE Size               4.00 MiB
Total PE              238466
Free PE               0
Allocated PE          238466
PV UUID               jI2Ir0-0Wbe-Gi1H-BxfX-5pTn-hOkO-W1qWZt

--- Physical volume ---
PV Name               /dev/mapper/luks-3a17bbe1-...
VG Name               vg_iridium
PV Size               223.08 GiB / not usable 0   
Allocatable           yes (but full)
PE Size               4.00 MiB
Total PE              57108
Free PE               0
Allocated PE          57108
PV UUID               10EZFc-LLD2-lve7-bM7E-YU7f-rNpe-A0jW8q

"/dev/sdc1" is a new physical volume of "931.51 GiB"
--- NEW Physical volume ---
PV Name               /dev/sdc1
VG Name               
PV Size               931.51 GiB
Allocatable           NO
PE Size               0   
Total PE              0
Free PE               0
Allocated PE          0
PV UUID               0gROMW-kB52-BLrr-hIf4-lGP6-XTnf-YOcyS7

I tried using

cryptsetup luksFormat /dev/sdc1

and it asked me for a new password. Not sure how to proceed, I thought I’d better ask for pointers than mess the system up.

The question is can I add a new drive to a LUKS encrypted logical volume?

I found this answer: Resizing a LUKS encrypted volume to a similar query but the answer states that I should unmount the filesystem first. The problem is that my filesystem is used so how can I unmount it?

Any pointers are more than welcome. Thanks!

My answer:


If you use the same passphrase as for your other volumes, then they will all be unlocked at the same time whenever you boot the system. Otherwise you’ll get two different (and confusing) passphrase prompts every time you boot.


View the full question and answer on Server Fault.

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