LVM1 to LVM2 plans for FC2

[Paul Jakma]

On Mon, 9 Feb 2004, Alexandre Oliva wrote:

> On Feb  6, 2004, Paul Jakma <paul at clubi.ie> wrote:

> > I dont. There's /no/ value in that IMO. root fs'es should be
> > small and as easy to boot as possible. Anyone who doesnt have
> > their root fs's like that is just someone who is waiting to learn
> > a lesson. :)

> Well, see...  /boot is pretty small, but the root filesystem
> (including /usr) has grown a lot over the past few years.

Ah, well, /usr should not be on root IMHO.

# df -h /
Filesystem            Size  Used Avail Use% Mounted on
/dev/md0              292M  195M   82M  71% /
# du -sh /boot/ /root/
21M     /boot
4.1M    /root

So, FC1 root (at least for this server), excluding /boot and ~root,
is 170M.

> Had I set aside a 5GB partition for that say 2 years ago, since
> that was a lot more than enough for a full install, I'd hardly be
> able to do a full install on it nowadays.  One of the reasons to
> use LVM is to make filesystems easier to grow and manage.

Ditto, hence why stuff like /usr should not be on root. 

> Say, if I want to install yet another experimental release, I just
> create a new logical volume for it.  No need to go find room for a
> non-LVM partition in one of the 8 disks on my desktop.

How do resize your root though? Given that it's very difficult to do,
from the system itself, it's surely better to have a small root. Eg,
I can resize /usr without rebooting. There are other benefits too,
eg, the smaller and simpler root is, the lower the likelihood of
(hopefully rare) software bugs in fs code hitting my root partition,
statistically one would hope these'd be exposed in other bigger and
more heavily used partitions than the smallest (and rarely written
to) partition on the machine.

It's always been best practice to use minimal root fses, i thought?

> I think there are some pains to the general case, and greater pains
> for the root-in-LVM case.

I guess I'll have to do some experimentation with converting from
2.4+LVM1 to 2.6+LVM2 on throwaway installs (eg UML) to see how it
goes.

regards,
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