In DRBD, resource is the collective term that refers to all aspects of a particular replicated data set. These include:
Resource name. This can be any arbitrary, US-ASCII name not containing whitespace by which the resource is referred to.
Volumes. Any resource is a replication group consisting of one of more
volumes that share a common replication stream. DRBD ensures write
fidelity across all volumes in the resource. Volumes are numbered
0, and there may be up to 65,535 volumes in one
resource. A volume contains the replicated data set, and a set of
metadata for DRBD internal use.
drbdadm level, a volume within a resource can be addressed by the
resource name and volume number as
DRBD device. This is a virtual block device managed by DRBD. It has a device major
number of 147, and its minor numbers are numbered from 0 onwards, as
is customary. Each DRBD device corresponds to a volume in a
resource. The associated block device is usually named
X is the device minor number.
udev will typically
also create symlinks containing the resource name and volume number, as in
Very early DRBD versions hijacked NBD’s device major number 43. This is long obsolete; 147 is the LANANA-registered DRBD device major.
Connection. A connection is a communication link between two hosts that share a replicated data set. With DRBD 9 each resource can be defined on multiple hosts; with the current versions this requires a full-meshed connection setup between these hosts (ie. each host connected to every other for that resource)
drbdadm level, a connection is addressed by the resource and the
connection name (the latter defaulting to the peer hostname), like