NAME

       drbd@.target - System target unit indicating a configured (optionally: promotable) DRBD
       resource

SYNOPSIS

       drbd@.target

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).

       Typical setups are using a cluster manager like pacemaker or the less feature rich but
       also less complex drbd-reactor to coordinate promotion attempts and service starts.

       But in situation where you "know" that you always want this node to promote and use DRBD
       and the peer(s) are never going to take over, but only used for "DR" purposes, then this
       target unit may be useful.

       It is intended to be used as dependency of any mount or other use of the specific DRBD
       resource. The implicit dependency on drbd@RESNAME.service will configure DRBD, an optional
       drbd-lvchange@RESNAME.service can be used to attempt to activate the backend logical
       volumes first. The optional (but in this scenario necessary)
       drbd-wait-promotable@RESNAME.service is then used to wait for DRBD to connect to its peers
       and establish access to good data.

EXAMPLE

       Assuming you have a DRBD resource named webdata, its backing devices being LVM logical
       volumes, with an xfs on one volume showing up as /dev/drbd0, this should make your boot
       sequence successfully mount that drbd to /mnt/point (unless DRBD really finds no access to
       good data in time, or some peer is already primary):

           systemctl enable drbd-lvchange@webdata.service
           systemctl enable drbd-wait-promotable@webdata.service
           echo "/dev/drbdX /mnt/point xfs defaults,nofail,x-systemd.requires=drbd@webdata.target 0 0" >> /etc/fstab

SEE ALSO

       drbd-reactor(1), drbd-reactor.promoter(5)

AUTHORS

       LINBIT HA Solutions GmbH https://linbit.com