A CMS is a complex system designed to solve several tasks at the same time. In contrast to an e-mail server, for example, whose only task it is to accept e-mail messages from senders and to send them to the recipients, CMS Fiona serves numerous editors, exports content in the background, provides its search engine with up-to-date content, and delivers (possibly dynamically created) content to the website visitors – to mention just the most important tasks.
Depending on the extent of these tasks, and on the degree to which their execution overlaps, more or less strain is put on the computer system on which these tasks are running. During normal operation of the CMS, each of these tasks uses different resources to a different and constantly changing extent.
Bottlenecks emerge if a resource (RAM, processor power, data throughput) is not available in the amount required to process the tasks in the desired period of time. This might sound trivial, it is, however, not trivial to determine the missing resources and to find the remedy. The following sections are intended to help you with this.
Editorial work with the CMS, i.e. with the Content Navigator, normally does not cause considerable load on the system, compared to the export or indexing of large amounts of data, for example. Particularly, the load cannot be determined only from the number of editors working with the system. It rather depends on the kind of work the editors are doing and how they use the Content Navigator:
The export is a process in which data from several sources is processed to generate the result – normally a web document. The more difficult it is to determine this data the more computational power is required for the export. The processor load is caused mainly by the queries and instructions in the layout files:
systemExecuteprocedures, formatters or callbacks) are called during the export. These procedures help to calculate data not part of the content itself or to format field values or links. Each call of such a Tcl procedure consumes computing time. Particularly, the manipulation of links by the link callback can considerably slow down the export because this callback is called for each link contained in the content of the file being exported.
If the export by the Template Engine and the Editorial System are running on the same computer, the response time of the system will be longer if the load is high. As a consequence, the editors will have to wait longer for GUI or preview pages to be fully displayed.
The live system does not require much computing power if mainly static content is delivered to the visitors. However, generating content dynamically using PHP or Java, for example, or intense use of portlets, requires computing power. This also applies to encrypting web pages and to large amounts of search requests.
The network bandwidth requirement of the live system mainly depends on the number of incoming requests and the amount of data to be delivered. If the demand is high, the bandwidth available for other tasks such as transferring the exported pages to the live server decreases.