Compressed objects and storage space

All of the licensed programs and some objects of the operating system ship in a compressed form. This requires less storage space on your server. The server decompresses objects according to certain criteria, which could affect the performance of the server.

System jobs (QDCPOBJx, where x is a number) automatically decompress these objects during the installation process if your system has sufficient unused disk storage. If enough storage space is not available, the system decompresses the objects when you use them, which could affect the performance of the system.

The server decompresses objects according to the following criteria:

• Greater than 750 MB available storage

  The system submits jobs to decompress all system objects just installed.

• 250-750 MB available storage

  The server decompresses only frequently used objects automatically. Object-usage information (the number of days an object has been used and the last-used date) is used to identify frequently used objects. The server decompresses any object that was used at least five times when the last use was within the last 14 days. The server leaves the remaining low-use objects in compressed form.

  • This does not include decompression of objects that are shipped in the operating system and in library QSYS. The system resets usage information for those objects during the installation process. For all other licensed programs, the object usage information is kept during the installation process.
  • A call to a system program does not update its usage information; the system does not automatically decompress programs in constrained storage mode. However, high-use programs ship in decompressed form and are not considered able to be compressed.
• Less than 250 MB available storage

  The system does not submit the decompression jobs and instead decompresses the objects as they are used.