Novell BUSINESS CONTINUITY CLUSTERING 1.1 SP2 - ADMINISTRATION Administration Manual page 19

Capability
Data-block replication between
sites
For information about data
replication solutions, see
Section 1.2.2, "Host-Based
versus Storage-Based Data
Mirroring," on page 14.
Clustered services
Cluster resource failover
Cluster resource configurations
Cluster resource configuration
synchronization
Failover of cluster resources
between clusters
Link latency between sites
Stretch Cluster
Yes; typically uses storage-based
mirroring, but host-based
mirroring is possible for distances
up to 10 km.
A single service instance runs in
the cluster.
Automatic failover to preferred
nodes at the other site.
Configured for a single cluster
Controlled by the master node
Not applicable
Can cause false failovers.
The cluster heartbeat tolerance
between master and slave must
be increased to as high as 30
seconds. Monitor cluster
heartbeat statistics, then tune
down as needed.
Cluster of Clusters
Yes; typically uses storage-based
mirroring, but host-based
mirroring is possible for distances
up to 10 km.
Each cluster can run an instance
of the service.
Manual failover to preferred
nodes on one or multiple clusters
(multiple-site fan-out failover).
Failover requires additional
configuration.
Configured for the primary cluster
that hosts the resource, then the
configuration is manually
replicated to the peer clusters.
Manual process that can be
tedious and error-prone.
Manual management of the
storage systems and the cluster.
Each cluster functions
independently in its own
geographical site.
Overview 19