Novell BUSINESS CONTINUITY CLUSTERING 1.1 SP2 - ADMINISTRATION, Руководство администратора

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Overview 19
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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
.
Yes; typically uses storage-based
mirroring, but host-based
mirroring is possible for distances
up to 10 km. Yes; typically uses storage-based
mirroring, but host-based
mirroring is possible for distances
up to 10 km.
Clustered services A single service instance runs in
the cluster. Each cluster can run an instance
of the service.
Cluster resource failover Automatic failover to preferred
nodes at the other site. Manual failover to preferred
nodes on one or multiple clusters
(multiple-site fan-out failover).
Failover requires additional
configuration.
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.
Capability Stretch Cluster Cluster of Clusters