[linux-lvm] Newbie questions

[Michael E Brown]

Hi Mayank!

On Wed, 24 Jan 2001, Mayank Vasa wrote:

> Hi,
>
> I am new to LVM and have some basic questions:
>
> 1) From the documentation I have read, I think once you extend/reduce a LV
> or VG you don't need to reboot the system. Correct?

You are correct. No need to reboot the system.

>
> 2) Assuming 1 is correct, how is the filesystem made aware of the changes?
> I'd like to understand the flow of this too.

You need to run a separate utility to resize the filesystem.

http://ext2resize.sourceforge.net/

There are kernel patches that allow you to do this while the filesystem is
online. Without the patches, you must un-mount the filesystem first.

No reboot necessary

>
> 3) What are LVM snapshots?

Very cool.
Copy-on-write. You create a snapshot of an LV. The original
volume is still read-write and acts normal. The snapshot acts like a
frozen-in-time picture of the original LV. It does this by creating
'before' copies of any blocks that are changed in the original LV.

--
Michael Brown