The basic configuration of a HiRDB/Parallel Server consists of a front-end server, dictionary server, and back-end server on the same server machine.
If the CPU workload of the server machine is low, multiple servers may be placed on one server machine. In such a case, more shared memory is required. If there is not enough shared memory, unit startup fails; for this reason, sufficient memory must be allocated.
Table 10-1 shows the permitted number of servers you can install.
Table 10-1 Number of permitted servers
Item | Number of permitted servers |
---|---|
Number of system managers | 1 |
Number of front-end servers | 1 to 1,024 |
Number of dictionary servers | 1 |
Number of back-end servers | 1 to 16,382 |
Number of servers per unit | 1 to 34 |
The server machine on which the system manager is defined should be at a location that is easily accessible by the HiRDB administrator for the following reasons:
When a complicated retrieval such as join processing is executed, it is better for HiRDB to use a back-end server that does not have a database in order to improve performance. If the server machine has sufficient space and complicated retrieval processing is to be performed, installation of a floating server should be considered. When a floating server is installed, a HiRDB file system area for work table files must be created. The name of this HiRDB file system area is specified in the pdwork operand of the back-end server definition.
If the CPU workload for SQL processing is too high to be processed on the front-end server, multiple front-end servers can be set up. This is called multiple front-end servers; for details, see 10.1.3 Setting up multiple front-end servers.
The storage space required by the HiRDB/Parallel Server must be estimated for each server machine. For details about how to estimate the storage requirements, see 16.2 Estimating the memory size required for a HiRDB/Parallel Server.