Re: How to use dmsetuup?

[debian-user@howorth.org.uk]

tomas@tuxteam.de wrote:
> On Sat, Nov 04, 2023 at 01:20:08PM -0400, gene heskett wrote:
> 
> [...]
> 
> > Indeed it does clarify the mechanics. thank you. Now do I have to
> > zero them first before I can then create (pvcreate) them,  
> 
> Not necessarily. Unless, of course, there are sensitive data on them.
> 
> The process would go roughly:

I agree with what Tomas has said, but I would add a step before
creating the PVs.

    # partition your devices
    I usually put a small partition at the start of the disk and
    another small one at the end (these are protection against some
    kind of errors that can occur - you just leave them blank) and then
    create a single large partition using the rest of the space on the
    device for use by LVM.

    There doesn't seem much point in having more than one LVM partition
    on a device to me (as suggested below)?

>   # put the necessary PV metadata on your raw devices
>   pvcreate /dev/foo1 /dev/foo2 ...
> 
>   # make them to a volume group named my-volgroup
>   vgcreate my-volgroup /dev/foo1 /dev/foo2 ...
> 
>   # cut out a logical volume from that, named my-logvol
>   lvcreate --name my-logvol my-volgroup
> 
>   # put a file system on that logical volume
>   mkfs.ext4 /dev/mapper/my-logvol
> 
>   # mount it
>   mount /dev/mapper/my-logvol /home
> 
> Now convince your boot setup to add the logical vols
> and mount them (this somehow involves fstab).
> 
> Perhaps this [1] page is enlightening (just disregard the
> talk about vagrant(. I'm not yet quite sure you really
> want this, but hey. Learning new tricks is what keeps one
> happy.
> 
> In my case I actually have a volume group (spanning a single
> physical device), but the use case is different: the physical
> device is encrypted (laptops get lost) and I wanted to have
> several partitions on it (and still move space from the one
> to the other in a pinch).
> 
> Cheers & enjoy
> 
> [1] https://linuxhandbook.com/lvm-guide/