I've shrinked my /home from 2.7TB to 100G, I've extended /root, /usr, /tmp and /var but I have been looking for a way to create an /opt partition for 3 hours now, and can't find it.

The setup is 3TB luks encrypted partition on /dev/sdb3(container) inside it are my lvm partitions /root, /usr, /tmp, /var and /home in a Debian Wheezy system.

I used lvreduce, lvextend, e2fsck and resize2fs from a booted live cd to change to current partitions. With directions from tutorials and webpages, like this is one.

How do I create an /opt partition 23G from the unused space on /dev/sdb3?

I've tried this:

lvcreate -L 23G -n opt Group

I don't understand this enough to find the right command, here is the output:

/dev/group/opt: not found: device not cleared
Aborting: Failed to wipe start of new LV


Here is fdisk -l

Disk /dev/sdb: 3000.6 GB, 30005929282016 bytes

Device Boot       start          end           Blocks     Id system
/dev/sdb1           1            4294967295   2147483647+ ee  GPT

Disk /dev/mapper/crypt1: 3000.3 GB 3000332451840 bytes
255 heads, 63 sectors/track, 364769 cylinders, total 58600024320 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/0 size (minimum/optimal): 4096 bytes / 4096 bytes

Disk /dev/mapper/group-root: 5716MB, 5716836352 bytes

Disk /dev/mapper/group-usr: 105,6 GB

Disk /dev/mapper/group-var: 10.5 GB

Disk /dev/mapper/group-swap 8048MB

Disk /dev/mapper/group-tmp 7914MB

Disk /dev/mapper/goup-home 107.4GB

Here is parted /dev/sdb print devices:

/dev/sdb (3001GB)
/dev/mapper/group-tmp (7915MB)
/dev/mapper/group-swap (8049MB)
/dev/mapper/group-home (107GB)
/dev/mapper/group-var (10.5GB)
/dev/mapper/group-usr (106GB)
/dev/mapper/group-root (5717MB)
/dev/mapper/crypt1 (3000GB)

Here is parted /dev/sdb print free:

Model: ATA TOSHIBA (scsi)
Disk /dev/sdb: 3001GB
Sector size (logical/physical): 5128/4096B
Partition Table: gpt

Number  start         end      Size         File system   Name   Flags
        17.4kb      1049kb    1031kb         Free space
1       1049kb      2097kb    1049kb                         bios_grub
2       2097kb      258MB     256MB          ext2
3       258MB       3001GB    3000GB
        3001GB      3001GB    466kb          Free space


Here is vgdisplay:

---- Volume group -----
VG Name           Group
Format             lvm2
Metadata Areas        1
Metadata Sequence No 18
VG Access       read/write
VG Status       resizable
MAX LV                0
Cur LV                6
Open LV               0
Max PV                0
Cur PV                1
Act PV                1
VG Size             2.73 TiB
PE Size             4.00 MiB
Total PE            715334
Alloc PE / Size     58461 / 228.36 GiB
Free PE / Size      656873 / 2.51 TiB
VG UUID             239082309572039572039
  • Maybe I'm missing something obvious. You say /dev/sdb3 is LUKS encrypted, but not what the LUKS container actually contains. Is that part of the LVM setup? Or is it currently not used for anything at all?
    – user
    Mar 17, 2015 at 22:30
  • @MichaelKjörling You have to excuse my little-know but I don't fully understand lvm yet. But as I understand it there is sdb which has sdb3 which is encrypted and inside that is my lvm with these partitions, where I want to add an /opt partition to lvm. If I shrink my /home from 2.7TB to 100G there should be alot of free space inside this sdb3. Or maybe I'm just rambling. Mar 17, 2015 at 22:36
  • So /dev/sdb3 is a LUKS container which in turn holds your LVM container (within which you created the LVs for various file systems), correct?
    – user
    Mar 17, 2015 at 22:37
  • 1
    Google suggests that adding -Z n to the lvcreate command might make the problem go away. If that fails please re-run the lvcreate command with a triple verbose flag, lvcreate -vvv ... Mar 18, 2015 at 0:04
  • 1
    Ahh....asked for the verbose output....vgdisplay -v group
    – mdpc
    Mar 18, 2015 at 0:13

1 Answer 1


The apparent answer is to run these two commands

lvcreate --name opt --size 23Gi group
mkfs -t ext4 -L opt /dev/group/opt

However, via the comments thread it became apparent that lvcreate threw an error message,

/dev/group/opt: not found: device not cleared
Aborting: Failed to wipe start of new LV

A search on Google finds that this is a known error, and the suggested workaround is to avoid zeroing the first part of the LV by using lvcreate --zero n ....

I've done some more investigation and it appears that lvcreate will work fine once udev is restarted (either via a system reboot or with udevadm reload). I would surmise that the /dev/{volumegroup} node is simply not being created, and so lvcreate can't find it.

(Answer extracted from the comments thread)

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