In DRBD, every resource has a role, which may be Primary or Secondary.
![]() | Note |
---|---|
The choice of terms here is not arbitrary. These roles were deliberately not named "Active" and "Passive" by DRBD’s creators. Primary vs. secondary refers to a concept related to availability of storage, whereas active vs. passive refers to the availability of an application. It is usually the case in a high-availability environment that the primary node is also the active one, but this is by no means necessary. |
The resource’s role can, of course, be changed, either by manual intervention or by way of some automated algorithm by a cluster management application. Changing the resource role from secondary to primary is referred to as promotion, whereas the reverse operation is termed demotion.