[systemd-devel] udevadm settle takes too long to finish

[Robert Milasan]

On Mon, 09 Dec 2013 11:33:03 +0100
"Thomas Bächler" <thomas at archlinux.org> wrote:

> Am 07.12.2013 22:29, schrieb Robert Milasan:
> > From systemd-analyze dump:
> > 
> >         Wants: systemd-udevd.service
> >         WantedBy: lvm2-activation-early.service
> >         WantedBy: lvm2-activation.service
> >         Before: lvm2-activation-early.service
> >         Before: sysinit.target
> >         After: systemd-udev-trigger.service
> >         After: systemd-journald.socket
> >         References: systemd-udevd.service
> >         References: systemd-udev-trigger.service
> >         References: sysinit.target
> >         References: systemd-journald.socket
> >         ReferencedBy: lvm2-activation-early.service
> >         ReferencedBy: lvm2-activation.service
> 
> What's the distribution you are using? Using udevadm settle for lvm
> is a waste of boot time and isn't even guaranteed to work (ask
> Lennart, Kay or Greg K-H for the full speech). It's a hackish
> workaround for LVM's inability to activate volumes automatically.
> 
> Instead, a socket-activated lvmetad service should be used in
> combination with the correct udev rules. The service files are
> provided by LVM, but they reference weird redhat-specific units and
> from what I saw have too many orderings, which results in slowing
> everything down needlessly.
> 
> Currently, I use 69-dm-lvm-metad.rules provided by LVM in combination
> with the unit files [1] and [2] (derived from the redhat units
> included in LVM). This is fast and works great for me, although
> lvmetad has some annoying bugs which have been reported to me, but
> which I could never reproduce.
> 
> There is no way to make udevadm settle "faster" and the only solution
> is (as Kay said already) is not using it.
> 
> [1]
> https://projects.archlinux.org/svntogit/packages.git/tree/trunk/lvmetad.service?h=packages/lvm2
> [2]
> https://projects.archlinux.org/svntogit/packages.git/tree/trunk/lvmetad.socket?h=packages/lvm2
> 

The distro is openSUSE and we are using lvm2-activation-generator which
comes with lvm2 package:

https://git.fedorahosted.org/cgit/lvm2.git/tree/scripts/lvm2_activation_generator_systemd_red_hat.c

-- 
Robert Milasan

L3 Support Engineer
SUSE Linux (http://www.suse.com)
email: rmilasan at suse.com
GPG fingerprint: B6FE F4A8 0FA3 3040 3402  6FE7 2F64 167C 1909 6D1A
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