Server processes or system servers for HiRDB on the standby system can be activated in advance, not during system switchover. This function is called the rapid system switchover facility. The time required for system switchover is reduced by the amount of time that would have been required for the activation processing of the server processes or system servers during system switchover.
The rapid system switchover facility is more effective in reducing the time required for system switchover than user server hot standby (the rapid system switchover facility includes the functionality of user server hot standby). Figure 25-76 compares the system switchover times of the two system switchover facilities.
Figure 25-76 Comparison of system switchover times
The unit that uses the rapid system switchover facility cannot inherit IP addresses. Therefore, in the case of a HiRDB/Single Server, configure the unit so it does not inherit IP addresses.
Configure the unit that uses the rapid system switchover facility so it does not inherit IP addresses. Specify N in the pd_ha_ipaddr_inherit operand in the unit control information definition for the applicable unit. Units that do not use the rapid system switchover facility can be configured to inherit IP addresses.
Hitachi recommends allowing use of the rapid system switchover facility on a back-end server unit and not allowing its use on a unit for the system manager or a front-end server. If a unit for the system manager or a front-end server is configured to not inherit IP addresses, operation after system switchover is more difficult than on a unit configured to inherit IP addresses. For system configuration examples, see 25.18.3 System configuration examples when using the rapid system switchover facility.
Before activating the running system and standby system HiRDB (or unit), start the IP addresses specified in the -x and -c options of the pdunit operand. Do not specify an IP address specified in the -x or -c option of the pdunit operand in the alias operand value's .up or .down file for HA monitor. If IP addresses for client connection are to be inherited, specify these IP addresses. If there are no IP addresses to be inherited, such as IP addresses for client connection, either specify nouse in the lan_updown operand of HA monitor's server definition statement or delete the alias operand value's .up and .down files.
To use the rapid system switchover facility, specify standbyunit in the pd_ha_agent operand.
In the case of a HiRDB/Parallel Server, consider whether or not to use the transaction queuing facility. When the transaction queuing facility is used, fewer transaction errors will occur during system switchover. For details about the transaction queuing facility, see 25.19 Transaction queuing facility.