Re: NetBSD 8: Install on an LVM partition

[Brad Spencer <brad%anduin.eldar.org@localhost>]

mlelstv%serpens.de@localhost (Michael van Elst) writes:

> moocan2112%yahoo.fr@localhost (moo can) writes:
>
>>Hello,
>>I'm trying to install NetBSD 8 using/inside a LVM partition.I would like to=
>> be able to resize partition if needed.I come from Linux and always use an =
>>LVM for /boot, /, swap, /home, /var
>
> Simple answer, you cannot.
>
> LVM is mostly a userland thing and requires a running system to start. This
> forbids at least using LVM for the root but also the standard swap/dump
> partitions.
>
> There could be a solution as used for full disk encryption, but I haven't
> seen anyone doing this. You can find details (for cgd) at
> https://wiki.netbsd.org/security/cgdroot/.

This is getting a little off topic, but I have done that...

I booted a laptop with a thumb drive which had a custom /etc/rc.d set up
that prompted for the cgd password to decrypt the hard drive that was in
the laptop.  I then used the init.root sysctl to pivot the root
file system over to the laptop hard drive.  The new root was a simple
cgd partition, and the rest of the filesystems were carved out using
LVM.  That is a small cgd0a for the new root, a cgd0b for swap, and the
rest of the disk LVM with /usr, /var, etc...  The laptop was also a Xen
DOM0, so the LVM was carved up into DOMU space too...  All encrypted
except for the thumb drive.

I was not able to get the new root filesystem, the cgd one, to use LVM
as thumb drive utilized /rescue for its programs and /rescue does not
contain any LVM utilities.  It might have been possible if I would have
put the LVM utilities on manually, but that would have made the creation
and updating of the boot drive harder.

> Everything else could be logical volumes, but on a single disk system you
> would need to create some hybrid partitioning scheme which is hardly worth
> the effort. Using LVM for data disks (including things like /home) works
> fine.
>
> Please also note that our LVM only implements a subset. We still lack
> a mirror target, so LVM raid or even just moving LVs online is not yet
> supported.
>
> -- 




-- 
Brad Spencer - brad%anduin.eldar.org@localhost - KC8VKS - http://anduin.eldar.org