Re: discuss about commit 3b0f9ce: filter-mpath: get wwids from sysfs vpd_pg83

[David Teigland <teigland@redhat.com>]

On Tue, Nov 14, 2023 at 08:55:39AM +0100, Peter Rajnoha wrote:
> On 11/13/23 19:38, David Teigland wrote:
> > - In general, it's old versions of lvm that we're discussing here.
> > Current lvm uses system.devices by default, where none of this is
> > relevant.  We can just turn off a number of filters when system.devices is
> > in use, including filter-mpath and filter-md.  It may still be interesting
> > to look at improvements, but the context for that is older stable,
> > released versions.
> 
> Hmm, but to generate or update the system.devices file and to add a new
> entry there, we still need to check first whether it's a suitable device
> or not, right? Like not being a multipath component...

If they know what they're doing, a user won't add a multipath/md component
to system.devices (or other unusable devices.)  However, it makes sense to
apply these checks when a device is added to system.devices to catch user
mistakes.  Also for vgimportdevices -a where a specific device is not
named.  The checks become a one-time thing, done when adding the device.
The checks are not needed by ordinary lvm commands, and are not being run
at tricky times like boot or for event handling.

Dave