Re: LVM root?

[dtutty@porchlight.ca]

On Wed, Oct 11, 2006 at 05:20:58PM -0400, dtutty wrote:
> On Wed, Oct 11, 2006 at 12:27:12PM -0400, Lennart Sorensen wrote:
> > On Wed, Oct 11, 2006 at 06:04:43PM +0200, Daniel Tryba wrote:
> > > Adding a disk creates an other copy of /, and with the newer
> > > kernels a raid5 array can be expanded, so it can be used by the LVM.
> > > 
 
Where can I find documentation on what is currently possible with raid
and lvm?  The software-raid howto says that resizing is impossible/very
difficult.  

If I install without raid, how difficult is it to add raid1 to / when I
add a second drive later on?  I had planned that my first upgrade (in a
few months) would be a second 1GB ram stick then a TV tuner card, then a
second larger drive for space/performance when removing commercials from
old VHS tapes (and making DVDs).  By then, larger drives will be
cheaper.

The downside of raid1 to me has always been that if I want to add 'a'
drive, I have to add 'a pair/set'.  I would like to be able to do this:

Start with one drive with lvm
Add a second drive and provide raid redundancy to / (e.g. raid1)
	and improve performance to the video-editing working directory
	(since I havn't got it installed, I don't know if this is /home
	or /var/tmp or what)
Add a third or more drives to add capacity while getting raid
redundancy.  This sounds like raid5.  Later-added drives will probably
be larger capacity.

If one can add a drive to raid5 and extend the pv onto it, then extend
the LV and the filesystem on it, while maintaining data redundancy,
that's almost perfect.  Perfect would be transparent data integrety
verification.

The question for me, on a limited budget, is how to start.  One disk,
with everything in place for adding a second, larger disk later.