System RDAREAs should be placed taking into account the placement of user RDAREAs. Points to be considered when a system RDAREA is placed are discussed below.
Among the system RDAREAs, data dictionary RDAREAs and data directory RDAREAs are accessed frequently by HiRDB for SQL statement analysis. If they are placed on the same disk as user RDAREAs, contention may occur between an access request for the purpose of SQL statement analysis and a table access request, in which case one of the requests is placed on hold until the other request has been processed.
Figure 10-8 shows an example of system RDAREA placement that can avoid contention among disk accesses.
Figure 10-8 Example of system RDAREA placement (HiRDB/Parallel Server)