root on LVM2: shutdown can't deactivate /

nielchiano · Veteran Joined: 11 Nov 2003 Posts: 1287 Location: 50N 3E

HI,

sorry if this is a dup. I was searched a bit and didn't find anything related, but the search-terms "root lvm" match quite a lot of posts. (I did find this, but this is another, related question)

I'm considering on putting my complete system (appart from /boot) on LVM2. I know putting / on LVM is not recommended, but the only reasons I found so far were: "need initrd to boot" and "hard to upgrade/rescue". I can live with those.

There is however a more serious problem. On my test setup I get a problem during shutdown. The init-scripts want to bring down LVM, which obviously fails, because / is still mounted (duh). In the script (/lib/rcscripts/addons/lvm-stop.sh) there is a link to https://www.redhat.com/archives/linux-lvm/2001-May/msg00523.html which explains the problem.

Basicaly, the post answers my question, but I'm concerned for the future: If a future release of LVM DOES update the metadata, it will become impossible to have my / on LVM. Is this problem solvable? or is root on lvm just "unsupported" and should I go cry in a corner?

wrs4 · Posted: Mon Jul 03, 2006 4:13 pm Post subject:

I'm curious...is there a particularly compelling reason to have / on lvm? The recommendations I saw on the gentoo lvm setup guide basically said to allocate a small amount of space for a non-lvm / partition (in my case I did 512 Mb) and then place other partitions you want on the lvs (for example, home, usr, var, etc).

nielchiano · Veteran Joined: 11 Nov 2003 Posts: 1287 Location: 50N 3E

wrs4 · Posted: Mon Jul 03, 2006 9:46 pm Post subject:

Nice response

I guess the way I look at it is....technically, / exists for mounting everything; not necessarily for containing everythng. So, a minimal / on a regular partition serves as a bare mount point for the stuff you need to have expandable (lvm) and for virtual filesystems (dev, shm, proc).

That's just me though

OTOH, if you can figure out a way to do it, more power to you.

nielchiano · Veteran Joined: 11 Nov 2003 Posts: 1287 Location: 50N 3E

wrs4 · Posted: Mon Jul 03, 2006 9:53 pm Post subject:

WTH?

You want /boot, a regular partition, to mount off /, an lvm partition? *shakes head in mock confusion*

How do you expect to be able to shut down the vgs and still have dev, proc, and shm operational if / is an lv?

nielchiano · Veteran Joined: 11 Nov 2003 Posts: 1287 Location: 50N 3E

wrs4 · Posted: Wed Jul 05, 2006 3:16 am Post subject:

I guess I can't see anything wrong with your logic, and a friend of mine tells me it works out of the box (as it were) for him on Debian. Hope you find a solution