5.2.3 Sharing HiRDB system definition files (HiRDB/Parallel Server)

For a HiRDB/Parallel Server, the HiRDB administrator must create HiRDB system definition files and manage them for each server machine. However, if the file sharing facility (NFS) provided by Hitachi CSMA/CD Network CD105 (TCP/IP) is used, all the HiRDB system definition files, except for unit control information definition files, can be managed by a single server machine. This is called sharing HiRDB system definition files. Figure 5-5 shows an example of sharing HiRDB system definition files.

Figure 5-5 Sharing HiRDB system definition files

[Figure]

Note
Shading indicates the shared files.
Organization of this subsection
(1) Differences depending on whether or not definitions are shared
(2) How to share HiRDB system definition files

(1) Differences depending on whether or not definitions are shared

When not sharedWhen shared
HiRDB system definitions must be managed for each server machine.HiRDB system definitions (except for unit control information definitions) can be managed by one server machine.
When the system common definition is modified, the same modifications must be made as many times as there are server machines.
For example, if there are four server machines, there are four system common definitions. Because the contents of these four system common definitions must be identical, all four definitions must be modified.
  • Because there is only one system common definition, necessary modifications need to be made only once.
  • Because there are fewer modifications to be made, the chances of making errors are reduced significantly.
  • If HiRDB can no longer reference the shared directory, HiRDB may terminate abnormally.

(2) How to share HiRDB system definition files

To share HiRDB system definition files, do the following:

  1. Create a directory to store the HiRDB system definition files that are to be shared. Create this directory at the server machine that is to manage the HiRDB system definition files that are to be shared. This directory is called the shared directory. These definition files can be managed by any server machine, but it is recommended that they be managed by the server machine where the system manager is defined.
  2. Create the HiRDB system definition files (except for unit control information definition files) under the shared directory.
  3. Create the unit control information definition files under $PDDIR/conf/ at each server machine. In this case, specify the name of the shared directory in the PDCONFPATH operand.