Re: [gentoo-user] Re: 500 meg / partition (including /boot) *WITHOUT USING LVM*

[Alan McKinnon <alan@linuxholdings.co.za>]

On Tuesday 04 September 2007, Remy Blank wrote:
> Neil Bothwick wrote:
> > Why do you make such a big deal of not using LVM? It achieves
> > everything you want to, and more, without the compromises.
>
> There's one thing that has prevented me from ever using LVM: the need
> to have an initrd (or initramfs). From what I remember, this has
> always required manually copying some utilities like the LVM tools to
> the initrd (or writing a script that does it), and remembering to do
> it every time I update one of the tools, and not to forget copying
> all required libraries as well, and so on.
>
> OTOH, I have stopped looking at solutions that need an initrd quite
> some time ago, so things might be easier nowadays. How do you manage
> your initrd? Do you even need one?

On Gentoo it's easy to get away with not using an initramfs. Everything 
is built from source and you roll your own kernel so we don't need to 
jump through the boot time hoops that a binary distro must to be able 
to support everything and boot.

You will always have a pretty good idea how much space / needs, it 
contains /bin, /sbin, /etc, /root and /lib. Unless oyu are in the habit 
of storing stuff in /root, 500M is plenty. So put / on a regular 
partition, everything else in LVM and your initramfs worries go away. 
The only case I can think of that *requires* initramfs right now is 
booting off a raid device

> > And what happens with 500GB is no longer enough and you want to add
> > more space. How do you resize your "partitions" to use space on the
> > second disk?
>
> Even though I have used resize2fs in the past, I have always thought
> that this tool was kind of a hack. Doesn't the resizing operation
> carry some risk? And if it goes wrong (e.g. a power outage), do you
> loose the complete content of the partition?
>
> And from what I remember, you can't resize a mounted ext3 partition,

balls. ext2online and resize2fs have been resizing ext3 partitions for 
ages. You can extend a mounted partition with ease and in safety.

What you can't do, and to my knowledge no regular fs can do, is to 
*reduce* a mounted partition

> so you have to boot to a rescue CD, hope that all your LVM tools are
> there (they normally are, but what version?) and perform the resize
> operation there.

Why would lvm not be on your rescue disk? That's just a silly excuse. 
What would you do with a reswcue disk that doesn't have fdisk on it? 
You'd throw it away and get a different one.

Versions don't have much impact on lvm. True, you can't use V1 tools on 
V2 volumes, but V1 hasn't seen much use since the days on kernel 2.4

> But I'd love to be proven wrong on all the points above! This would
> certainly motivate me to look into LVM seriously this time. It really
> seems to be the right solution to the various problems I have seen
> with static partitions.

You are imagining problems where none exist :-)

The only thing you need worry about is where are you going to get a 
decent howto that explains the concepts. You are dealing with three 
layers of stuff on top of physical partitions and some docs out there 
are ... confusing. Once you get the picture fully, it's as easy pie and 
makes perfect sense.

Really, LVM is the answer to all those prayers you have been sending up 
to $DEITY for years :-)

alan



-- 
Optimists say the glass is half full,
Pessimists say the glass is half empty,
Developers say wtf is the glass twice as big as it needs to be?

Alan McKinnon
alan at linuxholdings dot co dot za
+27 82, double three seven, one nine three five
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