10.2.2 Designing HiRDB file system areas for system files

This section discusses the design considerations for HiRDB file system areas in which system files are to be created.

Organization of this subsection
(1) Design for improved reliability
(2) Design for improved performance

(1) Design for improved reliability

  1. For update processing, character special files are more reliable than regular files. Regular files may become inaccessible after a system shutdown. Thus, character special files should be used for HiRDB file system areas for system files.
  2. Create at least two HiRDB file system areas for system files. If there is only one HiRDB file system area for system files, HiRDB cannot continue operating in the event of a hard disk failure at the disk containing the system files.
  3. Create HiRDB file system areas for system files on separate hard disks. In this way, in the event of a hard disk error, you can restart HiRDB using the other hard disk.
  4. The amount of space required for a HiRDB file system area is displayed when the system generator (pdgen) is executed. At least the displayed amount of space should be allocated to the HiRDB file system area.

(2) Design for improved performance

You should create HiRDB file system areas for system files on separate hard disks separately from the ones used for HiRDB file system areas for RDAREAs. In this way, you can distribute input/output operations when collecting a synchronization point dump, thereby reducing the amount of time required to collect the synchronization point dump.