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Installing the Software on a Cluster
All software components must be installed correctly to take advantage of the clustered environment. The following sections describe the basic principles of installing the software on a cluster. Refer to Clustering for a general overview of clustering concepts in relation to the software.
The software requires that each node within a cluster has the necessary software components and Windows registry information. Installing the software to be cluster-aware involves both the active and passive node installations of each component.
A physical installation of a software component is the default option when installing the software. When you choose a physical installation, the software is installed on a node or machine and acts independently of the cluster. Services installed in this way do not take advantage of clustering features like failover protection. If you intend to back up the CommNet Server database in the cluster group with the SQL iDataAgent as is recommended, then the Windows File System iDataAgent must be installed on each physical node in the cluster. See Books Online for more information on installing products.
Software components can also be installed to cluster servers. When this option is selected, the software will be installed to a cluster server and its associated disk group, and will be able to take advantage of cluster features such as failover. If all passive nodes are available, installations to the selected cluster server will update the active (owning) node and all passive nodes.
In some cases when your passive node was not available during the automated installation, you can perform a passive installation. The passive installation sets up other nodes within a cluster to take over for that active node in case of failure. This is performed after the active installation of each component so that the registry information can be duplicated from the active nodes to the passive nodes, where applicable. If any passive node was not available, follow the steps for manually installing a passive node provided in Manually Installing the Software on a Passive Node.
For example, suppose a cluster has five nodes (node1, node2, etc.). The automated installation sets up the CommNet Server software onto a cluster server hosted by node1. The software automatically retrieves the list of nodes to which node1 can failover. Let's assume that node3 is not available during the automated installation. The software automatically installs onto the active node (node1) and on all available passive nodes (node2, node4, and node5). After that, a separate passive node installation needs to be performed on node3 in order to prepare it for failover protection.
The CommServe must always be installed first in a CommCell. In a clustered environment, the CommServe software binaries are installed on the physical nodes (active, then all passive nodes) while the SQL database is installed on the cluster server. The install procedure is performed on the active node with the choice of an automated or separate install to all passive nodes, with no failover required at the end of the installation process. For any passive nodes unavailable at the time the install was performed from the active node to the cluster server, a separate install must be performed. Installed to each node, the CommServe software is tolerant to binary corruption; if the binaries are corrupted on one physical node, the cluster resources can fail over to another physical node, which has its own set of binaries, affording the same performance, reliability, and fault tolerance as a cluster provides for power, hardware, or application failure.
For software installation instructions for a clustered CommServe, see CommServe Deployment.
When the CommServe is to be installed in a cluster environment together with a Windows File System iDataAgent, also refer to Install the CommServe and Windows File System iDataAgent on the same Cluster Group.
The MediaAgent software can be installed in one of the following ways:
Install the MediaAgent software on the physical node. When you install the MediaAgent software on the physical node, you can use GridStor® to provide the necessary failover capabilities. See Alternate Data Paths (GridStor) - Clustered Environments for more information.
Clustering support is provided only for a library which is shared across a SAN in a non- DDS and in a DDS environment.
The index cache must be configured either on the shared disk or on a network share accessible to all the nodes on the cluster. The index cache should not be configured on the physical nodes.
For software installation instructions for a MediaAgent, see MediaAgent Deployment.
If you will be installing the File System iDataAgent on the cluster server, you must first install the File System iDataAgent on each physical node of the cluster.
For MSCS clusters, all configuration information is stored on a quorum disk that is selected during the installation of the Microsoft Cluster Server software. It is very important to Back Up Quorum Data, and this requires a File System iDataAgent on the physical server. The quorum databases are automatically backed up by the default subclient for the File System iDataAgent on each physical node. The Windows 2000 iDataAgent will include the quorum databases during a system state backup.
All iDataAgent installations should be performed after the CommServe, MediaAgent and any File System components are installed. To protect the data on the cluster group, the Agent software must be installed to the cluster server for every node in the cluster configured to host that cluster server. When the cluster server install procedure is performed on the active node, you can choose to perform an automated install to all available passive nodes at the same time.
For example, a cluster group running Microsoft Exchange, with node1 as the active node. To take advantage of failover protection, an installation of the Exchange iDataAgent software should be performed to the cluster server (and all available passive nodes) from node1, and then separately on any unavailable passive node(s). If not already installed, the Windows File System iDataAgent will be automatically installed in the cluster group with the Exchange iDataAgent.
For software installation instructions, see Installation.
Failure of the CommServe software on the active server will cause a failover to a standby server.
By default, a failure of the MediaAgent or any Agent software on the active node will not cause a failover to be initiated. To configure a cluster server to fail over when the MediaAgent or Agent software fails, after you have finished installing the appropriate software on all the nodes in the cluster, perform the following on each of the computers configured to host the cluster group:
Sample of the ClusterVolInfo.ini file:
[Volume1]
MountPath=E:\
VolumePath=\\?\Volume{fa36bc2f-8811-11de-84b4-806e6f6e6963}\
[Volume2]
MountPath=F:\
VolumePath=\\?\Volume{fa36bc30-8811-11de-84b4-806e6f6e6963}\
[VolumeN]
MountPath=X:\
VolumePath=\\?\Volume{dd8dd18e-1006-11db-858c-806e6f6e6963}\
In general, data protection operations in a cluster environment function as they do in a non-clustered environment. However, it is recommended that you include the shared data for data protection operations only on the shared disk, and conversely, that you include local data for each physical server only on the physical server's local disk, using the appropriate Agent software on the physical server to back up this disk.
For additional cluster-specific information related to backups, refer to Backup Filters for Windows Clusters and Backing Up Quorum Data for MSCS Clusters.
In general, data recovery operations in a cluster environment function as they do in a non-clustered environment. You can restore data that resides locally on a physical node, or that resides on the cluster group's shared disk, just as you would restore data for a non-clustered computer. The process of restoring client data to a cluster group is the same as it is on a non-clustered computer; the nodes in the cluster group is viewed as another computer on the CommCell.
Note that the cluster server always requires that at least one physical server is up and running. Therefore, if all the physical servers fail, be sure to restore at least one of these servers before you restore the cluster server.
Consider the following in the event of a failover:
| WARNING Do not specify this occurrence of MediaAgent in any operations such as Data Path. |
A specific Product License must be available for each component you install, whether CommServe, MediaAgent, or Agent, and a license is consumed for each installation. When a File System Agent is installed on a cluster group, a special license is required, for Virtual File System.
As an example of a Windows cluster, consider one with three physical nodes and Microsoft SQL server on the cluster server. License requirements would be as follows: