drbd-wait-promotable@.service(7)
================================

Name
----
drbd-wait-promotable@.service - Wait for DRBD to become promotable

Synopsis
--------
**drbd-wait-promotable@**__RESNAME__**.service** - Wait for DRBD to become promotable

Description
-----------
Usually you do not want to "hardcode" an unconditional promotion attempt of
DRBD resources, because you usually cannot know a-priory whether this instance
of DRBD will have access to good data (yet).

If you try to promote (mount, use) DRBD before it can be certain to have access
to good data, the attempt will fail in various ways, typically claiming "wrong
medium type", "need access to good data".

This unit will wait for the DRBD internal state to indicate that it has access
to good data.  It does *not* monitor the state further, so this is good enough
only to avoid trying to mount "too early" if you hard-code the mount attempt
into your boot sequence, for example using an 'fstab' entry or similar.

To monitor and react to DRBD state changes, use *drbd-reactor* or a cluster
manager like *pacemaker*.

If you `systemctl enable` this unit, it will be required by *drbd@.target*,
so anything depending on that target, for example an fstab entry, will
implicitly wait until this DRBD indicated it was "healthy enough" to be used.

It can still timeout, in which case systemd sees this as a start failure, and
starting of any dependencies (e.g. the mount) won't be attempted at this point.

See Also
--------
linkgit:drbd@.service[7],
linkgit:drbd@.target[7],
linkgit:drbd-lvchange@.service[7]

