A collection of multiple server computers into a single unified cluster provides
an added measures of performance, reliability, and fault tolerance. The CommServe,
MediaAgent, and supported Agents take advantage of the failover protection afforded
in the clustering environment. If an active node fails, the
software will still be able to function from the node that has not failed, and will
continue to be able to perform data protection and recovery operations.
You can
create schedules for data protection operation on cluster servers in the
same way as you create data protection operation schedules for data on a
physical node.
All schedules are saved on the CommServe. When a job is scheduled in
a cluster server, the CommServe executes that job on the active server.
If the active server fails while jobs are in progress, a failover will occur,
and running jobs are temporarily placed in a pending state. Once the failover
completes, the new active server will restart the jobs. In addition, remaining
scheduled jobs are implemented on this new active node. This is shown in
the illustration; the cluster server is associated with
Node A and Node
B. Since Node A is the active node
(and therefore has access to the shared disk), scheduled jobs for the virtual
server are executed on Node A. When
Node A fails, after the failover, a new
data protection operation is started on Node B
which is now the active node. In addition, the remaining scheduled jobs
are executed on Node B.
Regardless of the hosting node, the software can perform operations for
a virtual server, including data protection and recovery operations, as
long as the software has access to the network and to the virtual server's
network name and Internet Protocol (IP) address.
When referring to the physical servers that comprise a cluster group, individual computers
are referred to as nodes. The physical server may be called one of the following
depending upon the context in which it is being discussed: "physical computer,"
"physical node," "Client computer". Also, the "physical server" may be an "active
node" or a "standby (passive) node" depending on its role within the cluster environment
at a given point in time.
"Cluster Server" or "Virtual Node" refers to the hardware and software components
(Cluster Resource Group) within the cluster that are managed by Cluster Service
as a single, logical unit. The virtual server is actually not a physical computer
but a logical construct within the system. However, like the physical servers, the
virtual server has an Internet Protocol (IP) address and a network name. As such,
the virtual server secures its own license on the CommServe, and it has its own
registry information. This registry information is included on all physical nodes
in the cluster. Once the proper installations are made to the physical nodes, the
virtual server can be configured on each node to function within the clustering
environment.
"Cluster Service" refers to the collection of components on each node that
perform cluster-specific activity, managing the Cluster Resource Group.
The "Shared Disk" resource is connected to each physical computer. This disk
resource is designed to include shared data for CommCell operations (e.g., data
protection and recovery operations). Information that is relevant only to each physical
server should be included only on the physical server's
local disk and not on the shared disk.
After a computer has been added to a cluster as a new node, and has been verified
to be functional, you can install CommServe, MediaAgent or Agent software on it. MediaAgent or Agent software can also be installed as non-cluster-aware
(a "physical" installation.) Normal installation procedures can be used for this.
Before removing a node from a cluster, the CommServe, MediaAgent or Agent software
can be uninstalled and/or Deconfigured, if it is not running any jobs, and if it
is not the current active node. The normal uninstall and deconfiguration procedures
can be used for this. For more information and procedures, see
Uninstalling Components.
Every physical node in a cluster which is configured to host a given cluster server, must have the same TCP port numbers configured for that cluster server. For more information, see
Network TCP Port Requirements -
Clusters.
A collection of multiple server computers into a single unified cluster provides
an added measures of performance, reliability, and fault tolerance. The CommServe,
MediaAgent, and supported Agents take advantage of the failover protection afforded
in the clustering environment. If an active node fails, the
software will still be able to function from the node that has not failed, and will
continue to be able to perform data protection and recovery operations.