Installing HiRDB Advanced High Availability allows you to use the following functions:

• Standby-less system switchover facility
• System reconfiguration command (pdchgconf command)
• Dynamic updating of global buffers (pdbufmod command)

The standby-less system switchover facility implements a system switchover method that enables HiRDB to continue providing services when a failure occurs by transferring processing to another unit. Because the standby-less system switchover facility does not require that standby resources be placed in reserve, it is significantly more economical than the previously available system switchover facility (the standby system switchover facility). With the previous system switchover facility, you had to set aside a server, CPU, and memory resources to be available for transfer of operations in the event of a failure. With the standby-less system switchover facility, there is no need to provide these redundant resources. You simply register another server as the alternate, and that server's unit takes over processing if a failure occurs. Although the processing performance of the unit that has taken over may be degraded, the overall cost of the system is reduced because you can make more effective use of resources.

The standby-less system switchover facility includes the standby-less system switchover (1:1) facility and the standby-less system switchover (effects distributed) facility. For details about the standby-less system switchover facility, see 8.1 System switchover facility.

Previously, changing HiRDB system definitions meant having to stop HiRDB; however, by using the system reconfiguration command (pdchgconf command), you can change HiRDB system definitions without having to stop HiRDB. This allows you to perform system-related operations while HiRDB is running, such as changing the configuration of units or servers and adding system files. For details about the system reconfiguration command, see 6.5.4 System reconfiguration command (pdchgconf command).

Previously, adding, changing, or removing global buffers required you to change the pdbuffer operand in the HiRDB system definitions, which meant you had to stop HiRDB. Using the pdbufmod command, however, allows you to add, change, and remove global buffers while HiRDB is running. This is called dynamic updating of global buffers. For details about dynamic updating of global buffers, see 6.8.1(3) Dynamic updating of global buffers.