Novell BUSINESS CONTINUITY CLUSTERING 1.2.1 - ADMINISTRATION, Руководство администратора, Страница: 19 / 184

Overview of Business Continuity Clustering 19
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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.
Table 1-3
Advantages and Disadvantages of Stretch Clusters versus Cluster of Clusters
Cluster resource configurations Configured for a single cluster Configured for the primary cluster
that hosts the resource, then the
configuration is manually
replicated to the peer clusters.
Cluster resource configuration
synchronization Controlled by the master node Manual process that can be
tedious and error-prone.
Failover of cluster resources
between clusters Not applicable Manual management of the
storage systems and the cluster.
Link latency between sites 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.
Each cluster functions
independently in its own
geographical site.
Stretch Cluster Cluster of Clusters
Advantages
Š
It automatically fails over when
configured with host-based
mirroring.
Š
It is easier to manage than separate
clusters.
Š
Cluster resources can fail over to
nodes in any site.
Š
eDirectory partitions don’t need to
span the cluster.
Š
Each cluster can be in different OUs
in the same eDirectory tree.
Š
IP addresses for each cluster can be
on different IP subnets.
Š
Cluster resources can fail over to
separate clusters (multiple-site fan-
out failover support).
Š
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.
Capability Stretch Cluster Cluster of Clusters