Veritas Storage Foundation 5.1 SP1 Cluster File System Installation Guide (5900-1510, April 2011)

■ Disconnect
■ Replica
Disaster
When the cluster on the primary site is inaccessible and appears dead, the
administrator declares the failure type as "disaster." For example, fire may destroy
a data center, including the primary site and all data in the volumes. After making
this declaration, the administrator can bring the service group online on the
secondary site, which now has the role as "primary" site.
Outage
When the administrator of a secondary site knows the primary site is inaccessible
for a known reason, such as a temporary power outage, the administrator may
declare the failure as an "outage." Typically, an administrator expects the primary
site to return to its original state.
After the declaration for an outage occurs, the RVGSharedPri agent enables DCM
logging while the secondary site maintains the primary replication role. After the
original primary site becomes alive and returns to its original state, DCM logging
makes it possible to use fast fail back resynchronization when data is
resynchronized to the original cluster.
Before attempting to resynchronize the data using the fast fail back option from
the current primary site to the original primary site, take the precaution at the
original primary site of making a snapshot of the original data. This action provides
a valid copy of data at the original primary site for use in the case the current
primary site fails before the resynchronization is complete.
See “Examples for takeover and resynchronization” on page 348.
See “Replica” on page 348.
Disconnect
When both clusters are functioning properly and the heartbeat link between the
clusters fails, a split-brain condition exists. In this case, the administrator can
declare the failure as "disconnect," which means no attempt will occur to take
over the role of the primary site at the secondary site. This declaration is merely
advisory, generating a message in the VCS log indicating the failure results from
a network outage rather than a server outage.
347Configuring a global cluster using VVR
Using VVR commands on SFCFS global clusters