On Thu, 22 Dec 2011 22:07:21 +1100, Russell Coker <russell@coker.com.au> wrote:
> On Thu, 22 Dec 2011, Goswin von Brederlow <goswin-v-b@web.de> wrote:
> > You only ever NEED stuff from outside LVM if you want to remove the VG
> > the system is on, which makes sense, or if you screwed up. E.g. when you
> > shrink the root LV without having shrunk the filesystem first and need
> > to undo that. At that point it becomes usefull to have access to the lvm
> > backup data, which is kind of hard if it is on lvm. If one has no
> > partition outside of LVM it is a good idea to copy a set of backup
> > metadata to an usb stick, just in case.
>
> If someone is concerned about possible LVM issues affecting the root
> filesystem then the easy solution is to just have the root filesystem
> (including /usr) outside LVM. The root filesystem isn't one that generally
> needs to be resized etc and even when /usr is included it's not particularly
> big by today's standards.
>
> It seems to me that wanting to have / outside LVM but /usr inside LVM is a
> fairly obscure corner case. If we are going to have to hack things to work
> differently from Fedora (and maybe miss some features along the way) to
> support such things then I think we shouldn't bother.
I agree, it's an obscure corner case, except for one tiny fact, which is
that it is the way I've been setting servers up for years, which means
that if I want those servers to continue to be as useful as they are now
I'll need to reinstall all of them eventually because of this change.
I was going to say that even my laptop is like that at present, although
I note that in a moment of madness I seem to have let / be put on LVM
for some reason, as you can see:
phil@poker:~$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/poker-root
485M 257M 204M 56% /
tmpfs 1.9G 0 1.9G 0% /lib/init/rw
varrun 1.9G 660K 1.9G 1% /var/run
varlock 1.9G 0 1.9G 0% /var/lock
udev 1.9G 348K 1.9G 1% /dev
tmpfs 1.9G 0 1.9G 0% /dev/shm
/dev/sda1 228M 73M 143M 34% /boot
/dev/mapper/poker-home
34G 32G 277M 100% /home
/dev/mapper/poker-usr
6.9G 6.5G 137M 98% /usr
/dev/mapper/poker-var
7.7G 6.1G 1.3G 84% /var
/dev/mapper/poker-srv
5.0G 327M 4.4G 7% /srv
/dev/mapper/poker-philmail
9.9G 7.9G 1.5G 85% /philmail
/dev/mapper/poker-debian
25G 16G 7.7G 68% /var/www/debian
tmpfs 2.0G 15M 2.0G 1% /tmp
/dev/ram1 23K 20K 3.0K 87% /home/phil/nobackup/.ram1
Amusingly, I just had to add another 500M to /usr in order to get that
listing to not show 100% for /usr, which I only noticed because I
decided to paste it here, so there you go for the need for resizing /usr
being a rarity :-)
Clearly I don't really care about the laptop, as demonstrated by the
fact that I didn't remember that / was on LVM until I looked, but that's
probably a fair compromise as I'm never going to need to do remote
repairs on it, an I _might_ run out of room on / since I play with new
software there -- on the servers the reverse is the case.
Cheers, Phil.
--
|)| Philip Hands [+44 (0)20 8530 9560] http://www.hands.com/
|-| HANDS.COM Ltd. http://www.uk.debian.org/
|(| 10 Onslow Gardens, South Woodford, London E18 1NE ENGLAND
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