[linux-lvm] Discussion: performance issue on event activation mode

[Martin Wilck]

On Tue, 2021-09-28 at 17:16 +0200, Martin Wilck wrote:
> On Tue, 2021-09-28 at 09:42 -0500, David Teigland wrote:
> 
> > 
> > Firstly, with the new devices file, only the actual md/mpath device
> > will
> > be in the devices file, the components will not be, so lvm will
> > never
> > attempt to look at an md or mpath component device.
> 
> I have to look more closely into the devices file and how it's
> created
> and used. 
> 
> > Otherwise, when the devices file is not used,
> > md: from reading the md headers from the disk
> > mpath: from reading sysfs links and /etc/multipath/wwids
> 
> Ugh. Reading sysfs links means that you're indirectly depending on
> udev, because udev creates those. It's *more* fragile than calling
> into
> libudev directly, IMO.

Bah. Mental short-circuit. You wrote "sysfs symlinks" and I read
"/dev/disk symlinks". Sorry! Then, I'm not quite sure what symlinks you
are talking about though.

Martin