Capacity and Performance Monitoring

Capacity Management

Release and Deployment Management

Release and Deployment Management is primarily covered in the Service Transition publication, but there are some aspects of this process which Service Operation staff will be involved with on a day-to-day basis. These may include:

• Actual implementation actions regarding the deployment of new release s, under the direction of Release and Deployment Management, where they relate to Service Operation components or services
• Participation in the planning stages of major new releases to advise on Service Operation issues
• The physical handling of CIs from/to the DML as required to fulfil their operational role s – while adhering to relevant Release and Deployment Management procedure s, such as ensure that all items are properly booked out and back in.

Capacity Management should operate at three levels: Business Capacity Management, Service Capacity Management and Resource Capacity Management.

• Business Capacity Management involves working with the business to plan and anticipate both longer-term strategic issues and shorter-term tactical initiatives that are likely to have an impact on IT capacity.
• Service Capacity Management is about understanding the characteristics of each of the IT service s, and then the demands that different types of user s or transaction s have on the underlying infrastructure – and how these vary over time and might be impacted by business change.
• Resource Capacity Management involves understanding the performance characteristics and capabilities and current utilization levels of all the technical component s (CIs) that make up the IT Infrastructure, and predicting the impact of any changes or trends.

Many of these activities are of a strategic or longer-term planning nature and are covered in the Service Strategy, Service Design and Service Transition publications. However, there are a number of operational Capacity Management activities that must be performed on a regular ongoing basis as part of Service Operation. These include the following.

All component s of the IT Infrastructure should be continually monitored (in conjunction with Event Management) so that any potential problem s or trends can be identified before failure s or performance degradation occurs. Ideally, such monitoring should be automated and threshold s should be set so that exception alert s are raised in good time to allow appropriate avoiding or recovery action to be taken before adverse impact occurs.

The components and elements to be monitored will vary depending upon the infrastructure in use, but will typically include:

• CPU utilization (overall and broken down by system / service usage)
• Memory utilization
• IO rates (physical and buffer) and device utilization
• Queue length (maximum and average)
• File store utilization (disks, partitions, segments)
• Application s (throughput rates, failure rates)
• Databases (utilization, record locks, indexing, contention)
• Network transaction rates, error and retry rates
• Transaction response time
• Batch duration profiles
• Internet/intranet site/page hit rates
• Internet response times (external and internal to firewalls)
• Number of system/application log-ons and concurrent users
• Number of network nodes in use, and utilization levels.

There are different kinds of monitoring tools needed to collect and interpret data at each level. For example, some tools will allow performance of business transactions to be monitored, while others will monitor CI behaviour.

Capacity Management must set up and calibrate alarm threshold s (where necessary in conjunction with Event Management, as it is often Event Monitoring tools that may be used) so that the correct alert levels are set and that any filtering is established as necessary so that only meaningful event s are raised. Without such filtering it is possible that ‘information only’ alerts can obscure more significant alerts that require immediate attention. In addition, it is possible for serious failure s to cause ‘alert storms’ due to very high volumes of repeat alerts, which again must be filtered so that the most meaningful messages are not obscured.

It may be appropriate to use external, third-party, monitoring capabilities for some CIs or component s of the IT Infrastructure (e.g. key internet sites/pages). Capacity Management should be involved in helping specify and select any such monitoring capabilities and in integrating the results or any alerts with other monitoring and handling system s.

Capacity Management must work with all appropriate support group s to make decisions on where alarms are routed and on escalation paths and timescales. Alerts should be logged to the Service Desk as well as to appropriate support staff, so that appropriate Incident Record s can be raised so a permanent record of the event exists – and Service Desk staff have a view of how well the support group (s) are dealing with the fault and can intervene if necessary.

Manufacturers’ claimed performance capabilities and agreed service level target s, together with actual historical monitored performance and capacity data, should be used to set alert levels. This may need to be an iterative process initially, performing some trial-and-error adjustments until the correct levels are achieved.

Note: Capacity Management may have to become involved in the capacity requirement s and capabilities of IT Service Management. Whether the organization has enough Service Desk staff to handle the rate of incidents; whether the CAB structure can handle the number of changes it is being asked to review and approve; whether support tools can handle the volume of data being gathered are Capacity Management issues, which the Capacity Management team may be asked to help investigate and answer.

Дата добавления: 2014-12-23