The lvm2-activation-generator is called by systemd(1) on boot to
generate systemd units at runtime to activate LVM2 volumes if
lvmetad(8) is disabled (global/use_lvmetad=0 lvm.conf(5) option is
used). Otherwise, if lvmetad(8) is enabled, the lvm2-activation-
generator exits immediately without generating any systemd units and
LVM2 fully relies on event-based activation to activate the LVM2
volumes instead using the pvscan(8) (pvscan --cache -aay) call that
is a part of udev(8) rules.
These systemd units are generated by lvm2-activation-generator:
lvm2-activation-early.service used for activation of LVM2 volumes
that is ordered before systemd's special cryptsetup.target to support
LVM2 volumes which are not layered on top of encrypted devices.
lvm2-activation.service used for activation of LVM2 volumes that is
ordered after systemd's special cryptsetup.target to support LVM2
volumes which are layered on top of encrypted devices.
lvm2-activation-net.service used for activation of LVM2 volumes that
is ordered after systemd's special remote-fs-pre.target to support
LVM2 volumes which are layered on attached remote devices.
Note that all the underlying devices (Physical Volumes) need to be
present when the service is run. If the there are any devices
presented in the system anytime later, any LVM2 volumes on top of
such devices need to be activated directly by lvchange(8) or
vgchange(8). This limitation does not exist when using lvmetad(8) and
accompanying event-based activation since such LVM volumes are
activated automatically as soon as the Volume Group is ready (all the
Physical Volumes making up the Volume Group are present in the
The lvm2-activation-generator implements the Generators Specification
as referenced in systemd(1).
This page is part of the lvm2 (Logical Volume Manager 2) project.
Information about the project can be found at
⟨http://www.sourceware.org/lvm2/⟩. If you have a bug report for this
manual page, send it to firstname.lastname@example.org. This page was obtained
from the project's upstream Git repository
⟨https://git.fedorahosted.org/git/lvm2.git⟩ on 2017-03-13. If you
discover any rendering problems in this HTML version of the page, or
you believe there is a better or more up-to-date source for the page,
or you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a mail
Red Hat, Inc LVM TOOLS 2.02.133(2)-git (201L5V-M029--A2C2T)IVATION-GENERATOR(8)