[CALUG] Upgrading from RH 7.3

[Dave Dodge]

On Tue, Feb 14, 2006 at 02:03:04AM -0500, Rajiv Gunja wrote:
> This way, even if you switch Linux distributions, you will have 1 partition,
> which will always be constant (/apps) so you can keep formating the other
> partitions.

Another option is to use LVM, which is effectively a way to let you
dynamically repartition.  You take all your free space and give it to
LVM to create a "volume group".  Then you can carve out "logical
volumes" as needed.  Each LV shows up in /dev and acts just like a
disk partition: you can use them for filesystems, mmap/dd raw data,
swap to them, etc.  Logical volumes can be created, deleted, and
resized on the fly.  With filesystems such as XFS you can extend a
logical volume and grow its filesystem without even unmounting it.

I normally install the OS onto a real partition and put most of my
data into LVM.  For example I might create a small filesystem for a
specific project, and then if the disk space gets tight I can grow the
filesystem later on.  You can put the root filesystem into LVM if you
want, but booting will then require an initrd/initramfs that knows how
to deal with it.

LVM has a few other tricks it can do, such as striping logical volumes
across drives (similar to RAID), copy-on-write snapshots, and
physically moving logical volumes between drives while they're in use.

                                                  -Dave Dodge