ELM Cluster Monitor is a free add-on to Event Log Monitor 2.2. ELM Cluster Monitor is a Microsoft Cluster Server resource DLL that enables you to manage resource failover groups within a Windows NT or Windows 2000 cluster.
As a Windows NT/2000 cluster administrator, you already know the importance and benefits of high-availability and keeping your servers as reliable as possible. By definition, the goal of a highly available system is to provide continuous use of critical data and applications that keep businesses up and running, regardless of planned or unplanned interruption. High-Availability refers to a system uptime that approaches 100%. Microsoft Cluster Server promises an availability level of 99.9%, which translates to approximately 8.7 hours of downtime per year. The only way to achieve expected levels of high-availability with Microsoft Cluster Server is to monitor and manage your clusters properly.
The need for high-availability is not limited to 365x24x7 environments. Many applications must be available during normal business hours or for a critical time periods throughout the day. A system failure during these critical periods is unacceptable for many organizations.
By itself, Microsoft Cluster Server does not provide much tracking or diagnostic information unless you enable special logging which add a significant amount of overhead to the system.
In Microsoft Windows NT 4.0, cluster logging has the following limitations:
- To enable cluster logging, you must restart the computer. With larger systems, this can take an appreciable amount of time. This also leaves the system in a state in which there is a possibility of lost client access if the other node were to go down.
- If logging had not been previously enabled, there is no way to enable it and process back to a problem. There would not be a history to any given problem.
- Resources are referenced by their Globally Unique Identifiers (GUIDs) instead of their friendly names, so reading the log is difficult and time consuming.
- No reference to a date other than the day of the month makes matching up the event log entries to the cluster log cumbersome if the cluster has been up for more than a month.
- Cluster logging resets itself when the service is restarted, so keeping a true history is not available.
Windows 2000 cluster logging is turned on by default, and it addresses these limitations to a certain extent. However, even with logging enabled, it is impractical to monitor this log file in real time.
That's where ELM Cluster Monitor comes in. ELM Cluster Monitor uses all seven sets of Cluster APIs to monitor the status of a Windows NT/2000 cluster in real-time:
- Cluster Management. ELM Cluster Monitor uses this set of APIs to collect cluster events, information on cluster objects (including the quorum), and overall cluster state information. This includes cluster-related events that do not get logged to the event logs.
- Cluster Database Management. ELM Cluster Monitor uses this set of APIs to monitor the cluster database. The cluster database, which contains data on all physical and logical elements in a cluster is stored in the Registry.
- Group Management. These APIs are used to monitor cluster failover groups (also known as resource groups) by tracking and reporting group status and membership changes.
- Network Interface Management. ELM Cluster Monitor uses these APIs to monitor the network interface(s) and report status changes, including those interfaces not monitored by the Cluster Service.
- Network Management. These APIs are used to monitor events related to networks being monitored by the Cluster Service. All networks available for use by the Cluster Service as the "heartbeat" network are monitored by the Cluster Service.
- Node Management. ELM Cluster Monitor uses these APIs to monitor and track node status, cluster membership and resource ownership.
- Resource Management. These APIs are used to monitor clusters at the Resource level, including the initiation of operations on the resource (stopping, starting, etc.).
ELM Cluster Monitor works with Build 2.2.1 and higher of Event Log Monitor 2.2. ELM Cluster Monitor is a free add-on; customers need only purchase the following to use ELM Cluster Monitor:
- An ELM Cluster Server Agent for each physical node in the cluster;
- An ELM Cluster Server Agent for each failover resource group being monitored
ELM Cluster Monitor System Requirements:
- Windows NT Server 4.0 - Enterprise Edition with Service Pack 5 or higher (SP6a recommended)
- Microsoft Cluster Server
- Windows 2000 Advanced Server of Windows 2000 DataCenter Server
- Windows 2000 Cluster Service
- Event Log Monitor - Enterprise Edition or Small Business Edition (Single Server Edition not supported)