Performance considerations for directly-attached optical media libraries

This topic discusses performance considerations that are specific to directly-attached optical libraries.

When a file has extended attributes, they are stored separately from the data. When the data is written or copied, the attributes must also be written or copied. If file attributes are not required, attribute copying can be suppressed when copying between the QOPT and QDLS files systems by using the Change Optical (CHGOPTA) command. Setting the copy attributes (CPYATR) value on the CHGOPTA command to *NO suppresses the copying of attributes between the QOPT and QDLS file systems.

• Expand buffer I/O with the HFS API
  Users of the HFS APIs can improve performance by taking advantage of the expanding buffer I/O option. Expanding the buffer I/O settings lets you control the amount of data that is read from the optical media when only parts of the entire file need to be read.
• Performance consideration for copying and duplicating optical volumes
  There are several performance considerations to be aware of when copying and duplication optical volumes.
• Volume mounting and dismounting schedule timers
  This topic provides information on how the iSeries™ server manages work requests to the directly attached optical library devices. It is a high-level view and does not include all program logic.