Databases Reference
In-Depth Information
In this case,
Application X
makes use of five services either directly or indirectly to
satisfy user requests. We need to monitor the individual services to get any idea as to
why an application may be unavailable to an end user. However, this is not sufficient
as some of the services may be required for execution and others may be optional.
For example, consider a shopping site. The catalog and order entry services must
be available to provide a service to the end user, but the fulfillment and payment
services need not be available, as they can do their work without the user being
online at the time. In this case, if the fulfillment service is unavailable, then the
application can still work, but it may have reduced functionality, such as being
unable to provide an immediate delivery date.
Another aspect of service monitoring that must be considered is the throughput on
individual services. This is important because individual services may be used by
multiple applications. Therefore, it is possible that an application that previously
gave excellent end-user response times may degrade its performance, because one of
the services it depends on is under heavy load from other applications. Monitoring
will allow this risk to be identified early on and corrective action can be taken.
