[linux-lvm] PFree is 0 on a drive with nothing on it

[Stuart D. Gathman]

On Thu, 5 Nov 2009, malahal at us.ibm.com wrote:

> Stuart D. Gathman [stuart at bmsi.com] wrote:
> > If you want an integrated LVM/filesystem, then you should look
> > at OpenSolaris and ZFS.  There are some advantages to this approach,
> > but it does mean that you have only one filesystem choice.
> 
> BTRFS is planning on doing similar things, in case you are not planning
> on jumping to Solaris yet. Stuart is right, you will be restricted to a
> single file system though.

Eventually, it might be possible to support arbitrary filesystems that
implement an API with operations like:

 o report extents that could be freed by an online resize
 o report extents that could be freed by an offline resize
 o online resize
 o offline resize

A filesystem could even return failure for resize operations, and the
filesystem aware LVM would then know it can't get free blocks from that
filesystem (which might result in an error message if it can't get them
from anywhere else either).

-- 
	      Stuart D. Gathman <stuart at bmsi.com>
    Business Management Systems Inc.  Phone: 703 591-0911 Fax: 703 591-6154
"Confutatis maledictis, flammis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.