Rich Freeman on 29 Sep 2013 04:53:11 -0700

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Re: [PLUG] Spanning volumes with LVM (Ubuntu)

On Sat, Sep 28, 2013 at 7:54 PM, Eric H. Johnson
<> wrote:
> At any rate, I have no idea how to undo where I am and start over. The 1TB
> drive (dsc) is now showing 2TB in size and coming in at sdb when it was
> originally sdc. Now I just want to blow everything away and start over, but
> I am not sure how to do that.

Define "blow everything away."  Does that include your original disk,
or just the new ones?  If you want to blow away everything then that
will depend somewhat on your distro and how its installer works,
unless you're doing it all manually.  If you're trying to just undo
what you did that might be possible, though looking below I'm not
entirely sure...

Drives moving around isn't unusual when you start adding them.  That
is one of the benefits of using LVM/mdadm/etc - you're using logical
names instead of physical drive references and during boot the system
is just going to scan everything and assemble things.

> Output from FDisk

There's your first problem.  You can't use FDisk with 3TB drives
unless you want to only get 2TB out of them.

> Disk /dev/sdc: 3000.6 GB, 3000592982016 bytes
>    Device Boot      Start         End      Blocks   Id  System
> /dev/sdc1            2048  4294967294  2147482623+  8e  Linux LVM

Yup - 2TB out of 3TB partitioned (sda wasn't partitioned)...

> Output from pvdisplay
> -----------------------------------------------------------
>   --- Physical volume ---
>   PV Name               /dev/mapper/sdb5_crypt
>   VG Name               ubuntu-vg
>   PV Size               931.27 GiB / not usable 2.00 MiB
> --- snip/arrange ---
>   --- NEW Physical volume ---
>   PV Name               /dev/sdb
>   VG Name
>   PV Size               2.73 TiB

Uh, you have something called sdb5_crypt and sdb.  Unless that mapper
name does not still correspond to the actual sdb drive you might have
a problem here - did you accidentally run pvcreate on /dev/sdb (thus
wiping out its partition table/etc)?  You might be stuck blowing
everything away.

It also looks like you might be mixing encrypted and non-encrypted
physical volumes in the same volume group.  Sure, you can do that, but
seems kind of pointless.  I'd pick one way or the other (and doing it
manually will be a pain!).  Chances are your distro set up
LVM+encryption for you initially, and in that case you might see if
they provide some fancy tool that automagically sets it up on multiple

If I were in your shoes I'd probably aim to backup whatever you can if
you don't already have backups.  If you can get at your data just take
one of those drives, partition it however you want, stick an ext3
partition on it, and copy your data over to it and just set it aside
initially.  Then I'd get everything working on the other two drives
and restore whatever is important back from the 3rd drive, and then
extend LVM onto it.

Again, I'd strongly consider using RAID, especially if you're starting
over anyway.  With 2x3TB + 1x1TB drives you could get 4TB of space.
To do that I'd probably have a small raid1 boot partition on all three
drives, a 3x1TB minus boot RAID5 partition across all three drives,
and then a 2x2TB RAID1 partition across the two larger drives.  Or you
can do what I did and live dangerously with btrfs.  :)

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