•
An IP Address resource is formed in the group and relates to the IP address by which the
group's virtual server is identified on the network.
•
A Network Name resource is formed in the group and relates to the name published on the
network by which the group is identified.
•
The Group is owned by one of the nodes of the cluster, but may transition to the other nodes
during failover conditions.
The diagram illustrates a cluster containing two nodes. Each node has ownership of one group.
Contained within each group are file shares that are known on the network by the associated
Network Name and IP address. In the specific case of Node1, file share Eng1 relates to
E:\Eng1
.
This file share is known on the network as
\\Fileserver1\Eng1
with an IP address of
172.18.1.99
.
For cluster resources to function properly, two very important requirements should be adhered to:
•
Dependencies between resources of a group must be established. Dependencies determine
the order of startup when a group comes online. In the above case, the following order should
be maintained:
1.
File Share—Dependent on Physical Disk Resource and Network Name
2.
Network Name—Dependent on IP Address
Failure to indicate the dependencies of a resource properly may result in the file share
attempting to come online prior to the physical disk resource being available, resulting in a
failed file share.
•
Groups should have a Network Name resource and an IP Address resource. These resources
are used by the network to give each group a virtual name. Without this virtual reference to
the group, the only way to address a share that is created as a clustered resource is by node
name. Physical node names do not transition during a failover, whereas virtual names do.
For example, if a client maps a network share to
\\Node1\Eng1
instead of
\\Fileserver1\Eng1
, when Node1 fails and Node2 assumes ownership, the map will become
invalid because the reference in the map is to
\\Node1
. If the map were created to the virtual
name and Node1 were to fail, the map would still exist when the group associated with Eng1
failed over to Node2.
The previous diagram is an example and is not intended to imply limitations of a single group or
node. Groups can contain multiple physical disks resources and file shares and nodes can have
multiple groups, as shown by the group owned by Node2.
Cluster planning
Requirements for taking advantage of clustering include:
•
Storage planning
•
Network planning
•
Protocol planning
Storage planning
For clustering, a basic disk must be designated for the cluster and configured as the Quorum disk.
Additional basic disks are presented to each cluster node for data storage as physical disk resources.
The physical disk resources are required for the basic disks to successfully work in a cluster
environment, protecting it from simultaneous access from each node.
The basic disk must be added as a physical disk resource to an existing cluster group or a new
cluster group needs to be created for the resource. Cluster groups can contain more than one
physical disk resource depending on the site-specific requirements.
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Cluster administration
