One of the most important jobs of the system administrator is to monitor activity on the system—for example, disk drive usage and CPU usage—and to deal with bottlenecks and other potential problems before they impact users. This section provides information on the system monitoring commands WHAT and POVF, as well as a few suggestions about potential problem areas, and guidelines for what to do about them. It also discusses the POKE and TANDEM commands, which are useful for monitoring and controlling system processes, as well as a group of commands that list user and system errors which are logged in the SECURITY-LOG and SYSTEM-ERRORS files.
Disk Drive Usage
The amount of information users can store on the disk drive is limited primarily by the physical capacity of the disk drive. Heavy system activity that causes fragmentation of available disk drive space can also inhibit efficient disk drive usage, as can badly sized files.
It is easy for users to fill even a very large disk drive very quickly. The amount of necessary available space can vary greatly depending on your installation, so you should take the time to learn the disk drive usage patterns on your system and be aware if the available space suddenly shrinks dramatically. To avoid problems, you should try to keep at least 20 percent of the available disk drive space free to allow for the creation of temporary files and other day-to-day fluctuations. Also, a number of administrative files (such as the ACC and SECURITY-LOG files) may need to be cleared periodically.
You can calculate the total amount of disk drive space for the data area by executing the WHAT command to determine the base frame ID number of the first data frame (SYSBASE) and the maximum frame ID on the system (MAXFID). Subtract SYSBASE from MAXFID to obtain the total size of the data area, in frames.
The following topics are presented in this section:
Monitoring and Controlling Processes
See Also
Optimizing Disk Drives Containing Virtual Memory Storage Files