Novell BUSINESS CONTINUITY CLUSTERING 1.1 SP2 - ADMINISTRATION Administration Manual page 20

Evaluating Disaster Recovery Implementations for Clusters
Table 1-3 illustrates why a cluster of cluster solution is less problematic to deploy than a stretch
cluster solution. Manual configuration is not a problem when using Novell Business Continuity
Clustering for your cluster of clusters.
Advantages and Disadvantages of Stretch Clusters versus Cluster of Clusters
Table 1-3
Advantages
Disadvantages
20 BCC 1.1 SP2: Administration Guide for NetWare 6.5 SP8
Stretch Cluster
It automatically fails over when
configured with host-based
mirroring.
It is easier to manage than separate
clusters.
Cluster resources can fail over to
nodes in any site.
The eDirectory partition must span
the sites.
Failure of site interconnect can
result in LUNs becoming primary at
both locations (split brain problem) if
host-based mirroring is used.
An SBD partition must be mirrored
between sites.
It accommodates only two sites.
All IP addresses must reside in the
same subnet.
Cluster of Clusters
eDirectory partitions don't need to
span the cluster.
Each cluster can be in different OUs
in the same eDirectory tree, or in
different eDirectory trees.
IP addresses for each cluster can be
on different IP subnets.
Cluster resources can fail over to
separate clusters (multiple-site fan-
out failover support).
Each cluster has its own SBD.
Each cluster can have an on-site
mirror of its SBD for high availability.
If the cluster of clusters uses host-
based mirroring, the SBD is not
mirrored between sites, which
minimizes the chance of LUNs at
both locations becoming primary.
Resource configurations must be
manually synchronized.
Storage-based mirroring requires
additional configuration steps.