[lvm-team] Soliciting feature requests for development of an LVM library / API

[Alasdair G Kergon]

On Mon, Dec 15, 2008 at 09:20:55AM -0500, Dave Wysochanski wrote:
> On Sat, 2008-12-13 at 15:23 +0000, Alasdair G Kergon wrote:
> > On Sat, Dec 13, 2008 at 03:28:20PM +0100, Kay Sievers wrote:
> > > On Sat, Dec 13, 2008 at 02:30, Dave Wysochanski <dwysocha at redhat.com> wrote:
> > > > Note that by scanning a single PV we may not be able to answer
> > > > definitively what VG it is in or what LVs it may contain.  So provided
> > > > we go this route with putting into the udev database all needed
> > > > information that today you get from pv/vg/lvdisplay commands, something
> > > > else will have to put together individual PV information to get an
> > > > accurate picture of the VG / LV info in the system.
> > When we discussed this with David in Boston, it became clear that the
> > udev database as currently implemented was unable to hold the information
> > LVM2 needs to store.
> What are the specific limitations of the udev database that make it
> unsuitable for LVM?
 
- Inability to store entities not directly related to known devices
  - Placeholders for PVs with known UUIDs but where the major/minor is not yet known
  - Volume Group information that links PVs together but will never be itself a device
- Difficulty of indexing by multiple keys to access the above info

Alasdair
-- 
agk at redhat.com