Re: [Libguestfs] [PATCH 4/5] daemon: lvm: list PVs/VGs/LVs with --foreign
On Tuesday, 26 July 2016 16:59:34 CEST Richard W.M. Jones wrote:
On Tue, Jul 26, 2016 at 05:41:28PM +0200, Pino Toscano wrote:
> The appliance has no LVM system ID set, which means that lvm commands
> will ignore VGs with a system ID set to anything. Since we want to work
> with them, pass --foreign at least when listing them to see them.
>
> See also lvmsystemid(7).
This is sort of a hack, if I'm understanding correctly.
Yes and no -- it's the only way we can deal with VGs with any system ID
set (which currently are not seen at all).
Can we not instead give the appliance a "system ID"?
This would be problematic, since new VGs would take the system ID of
the appliance, making them tied to that specific ID; on the other hand,
creating a VG from a LVM with no system ID set means it will be seen on
any LVM, regardless of their system ID.
Also, lvm(8) says:
--foreign
Cause the command to access foreign VGs, that would otherwise be
skipped. It can be used to report or display a VG that is owned
by another host. This option can cause a command to perform
poorly because lvmetad caching is not used and metadata is read
from disks.
which sounds bad.
No solution about this yet.
--
Pino Toscano
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