Re: *** ANNOUNCEMENT *** LVM 1.0 available at www.sistina.com

From: Andrea Arcangeli (andrea@suse.de)
Date: Wed Aug 15 2001 - 12:04:28 EST


On Wed, Aug 15, 2001 at 06:50:05PM +0200, Heinz Mauelshagen wrote:
> offset. No known way around this.

As said in the attached email (never got a reply about it yet btw)
there's definitely a way around it, there's no magic in the beta7
lvmtools, anything they can do can be done as well in the new lvmtools
if we want to (and I believe we want to). I understand you don't want to
clobber the core code with backwards compatibility cruft, but a new
backwards compatibility utility, even in a new directory to make obvious
nothing gets clobbered, could be developed and it would solve the
problem.

Andrea


attached mail follows:


On Tue, Jul 31, 2001 at 02:20:50PM +0100, Joe Thornber wrote:
> On Tue, Jul 31, 2001 at 03:13:17PM +0200, Andrea Arcangeli wrote:
> > On Tue, Jul 31, 2001 at 10:41:37AM +0100, Joe Thornber wrote:
> > > On Tue, Jul 31, 2001 at 11:25:14AM +0200, Andrea Arcangeli wrote:
> > > > then why don't you make a pvdisplay option in the new tools that allows
> > > > you to find where the PEs were positioned?
> > >
> > > The PE location was being calculated, based on various constants such
> > > as BLOCK_SIZE (which varied through the beta series), only the
> > > currently installed tools know where they were putting the PE's :(
> >
> > What's the problem? Just make a --something option that finds the
> > location of the PE using the previous BLOCK_SIZE.
>
> But what was the previous block size ? There's no way of knowing with the

The one defined in the beta7 lvmtools. The old tools know that, right?
Somebody has to know if the old tools can cope with it. Then just teach
that to the new tools too when the --something is passed to pvdisplay.

> current metadata format ... and BLOCK_SIZE is only one of the variables.

Then define all them, where's the problem? Not being able to use an old
pv after the new tools and new kernel is been installed is a kind of
showstopper situation for the end user as far I can tell. There's no
real technical reason for which we should take the the pain of this
showstopper situation IMHO, it is perfectly technically possible to
avoid that. Of course I know some more coding and testing is required to
handle that transparently, but it looks a very worthwhile effort to me.

Andrea
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