Novell BUSINESS CONTINUITY CLUSTERING 1.1 SP2 - ADMINISTRATION, Руководство администратора

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20 BCC 1.1 SP2: Administration Guide for NetWare 6.5 SP8
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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
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, or in
different eDirectory trees.
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.
Disadvantages
Š
The eDirectory partition must span
the sites.
Š
Failure of site interconnect can
result in LUNs becoming primary at
both locations (split brain problem) if
host-based mirroring is used.
Š
An SBD partition must be mirrored
between sites.
Š
It accommodates only two sites.
Š
All IP addresses must reside in the
same subnet.
Š
Resource configurations must be
manually synchronized.
Š
Storage-based mirroring requires
additional configuration steps.