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

Peter Rajnoha prajnoha at redhat.com
Tue Jun 8 15:19:32 UTC 2021


On Tue 08 Jun 2021 14:48, Martin Wilck wrote:
> On Di, 2021-06-08 at 15:56 +0200, Peter Rajnoha wrote:
> > 
> > The issue is that we're relying now on udev db records that contain
> > info about mpath and MD components - without this, the detection (and
> > hence filtering) could fail in certain cases. So if go without
> > checking
> > udev db, that'll be a step back. As an alternative, we'd need to call
> > out mpath and MD directly from LVM2 if we really wanted to avoid
> > checking udev db (but then, we're checking the same thing that is
> > already checked by udev means).
> 
> Recent multipath-tools ships the "libmpathvalid" library that
> could be used for this purpose, to make the logic comply with what
> multipathd itself uses. It could be used as an alternative to libudev
> for this part of the equation.

Ah, yes, sure! Still, we have the MD in play...

Out of curiosity - if you disable mpath and MD component detection in
lvm.conf, can you still hit the issue? (Of course, if you're not using
any of the two in your stack.)

Peter




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