T 4.20 Overloaded information systems
If information or communication systems such as hardware, software, or networks are dimensioned insufficiently, there will come a point when they no longer meet the requirements of the users. Depending on the type of affected systems, this may have numerous adverse effects.
Information systems may be overloaded by
- existing storage disk space capacities being exceeded, for example when the mailbox is overcrowded during longer absence of the owner,
- a system being overused by numerous simultaneous queries overloading the processors,
- the applications requiring too much computational power, e.g. if the process output is insufficient for intensive graphics applications,
- sending a large number of messages at the same time as a newsletter.
As a possible consequence, IT systems or services may be temporarily unavailable or data may be lost.
Each storage medium can only store a limited amount of data. When this limit is reached data may be lost or services are no longer available, for example:
- users can no longer save data,
- incoming emails are rejected and no emails can be sent,
- incoming and possibly outgoing faxes are interrupted,
- the logging function is disabled and/or protocol data not yet analysed is overwritten, or
- documents can no longer be archived electronically.
The capacity of the storage medium may be exhausted suddenly for different reasons, e.g. due to errors in application programs, increased memory requirements of the users, or even due to a targeted attack including the deliberate reduction of the existing disk space in order to prevent logging.
Generally, large amounts of data must be saved when archiving electronically. On the one hand, the amounts of data are caused by the large number of documents to be archived for certain files. On the other hand, each newly created version of a document is saved newly under a new version number.
Resources can also be overloaded deliberately when somebody generates an intensive demand for an operating resource provoking an intensive and permanent disturbance of the operating resource, see also T 5.28 Denial of services.