[NCLUG] I was stupid. Learn from my pain.

[Stephen Warren]

On 08/14/2014 10:12 PM, Grant Johnson wrote:
> Well, I added two more drives to a machine here at the house.    I made
> them a paired array that I intended to make into a physical volume to
> make more space for my stuff by adding it to the volume group.   So, I
> assembled the array, rebuild initramfs, rebooted to make sure it was OK,
> reset it to read/write, and all was well.   I had created md1 without
> any major issues.   Then a little fdisk /dev/md0 and create a partition
> on the disk, type of Linux LVM, write the partition table, and exit.
>
>
> Well, now I was sad.   No more useful response from pvs or lvs or vgs,
> reboot only loads initrd, then fails to start the LVM. Booting from the
> install media in recovery mode will build the array, but not see the LVM
> bits.  I had killed it, or so I thought.   Time to reinstall and start
> from backups again.   Well, I deleted the partition, and suddenly,
> pvscan found things!   Reboot and all is well, except for my stress level.
>
>
> Just in case any of you make this bonehead move and build a partition on
> a device defined to have the whole device be used as a physical volume.
> All may not be lost.

It's not clear what you did wrong from your description. FWIW, I have 
LVM PVs within partitions on my RAID-1 arrays (in order to have /boot 
outside LVM, on regular partitions on top of the RAID-1, on the same 
physical disks), and everything works fine...