Configuring a Service Level Monitoring Class (SLM Class)
To use Service Level Monitoring (SLM), add at least one SLM class to the Virtual Traffic Manager. Each SLM class contains the definition of its ideal response time and of thresholds for alerts and logging.
SLM classes are stored in the Service Level Monitoring catalog, and each class can be applied to one or more virtual servers.
Adding an SLM Class to the Catalog
To add a new SLM class, click Catalogs > SLM. In the box labeled “Create new service level monitoring class”, type a name for your new class and click Create Class.
Each SLM class contains a number of configurable settings, as follows:
Setting | Description |
|---|---|
response_time | The time limit, in milliseconds, against which the Virtual Traffic Manager measures response times. The Virtual Traffic Manager treats responses as conformant if the elapsed response time is shorter than or equal to this value. Responses that take longer than this value are non-conformant. For a description of how the Virtual Traffic Manager measures response time, see Introducing Service Level Monitoring. |
serious_threshold | If the percentage of conformant responses drops below this level, a SERIOUS-level event will be raised, and a SERIOUS-level message written to the event log. |
warning_threshold | If the percentage of conformant responses drops below this level, a WARNING-level event will be raised, and a WARNING-level message will be recorded in the event log. |
For example, you might set a response time of 1000ms, a warning threshold of 70% conformant responses, and a serious threshold of 40% conformant responses. This would mean that:
- If fewer than 70% of requests take less than 1000ms to return from a server, a warning entry is written to the Virtual Traffic Manager event log.
- If fewer than 40% of requests take less than 1000ms, a serious-level entry is written to the Virtual Traffic Manager event log.
The percentage of conformant requests is calculated from an average of the last 10 seconds’ of requests, comparing the number of requests that fell within the response_time threshold to the total number of requests monitored by that SLM class.
You can define Event Handlers to call actions when “warning” or “serious” level events are raised by an SLM class.
After you have configured the SLM class, click Update to commit your changes.