2.2.48 Operands related to HA groups

217) pdhagroup -g HA-group-identifier -u unit-identifier[,unit-identifier]...
When you are using the standby-less system switchover (effects distributed) facility, use this operand to define an HA group.
There is no upper limit on the number of HA groups that can be defined on a single system.
For details about HA groups, see the HiRDB Version 9 System Operation Guide.
-g HA-group-identifier
~<identifier>((1-8 characters))
Specifies an HA group identifier. Specify an identifier that is unique to an HA group within the system.
-u unit-identifier[,unit-identifier]...
~<identifier>((4 characters))
Specifies the unit identifier for the unit that comprises an HA group. The number of units that can be specified is between 2 and 32. Specifying duplicate units causes an error. The units to be specified in this option must satisfy all of the following conditions:
  • All units within the HA group belong to the same network segment.
  • The unit does not belong to another HA group.
  • The standby-less system switchover (effects distributed) facility is being applied. (pd_ha_agent = activeunits is specified.)
  • At least one host back-end server exists inside the unit. (An accepting-only unit cannot be defined.)
  • The number of host back-end servers within the unit plus the maximum number of guest back-end servers that can be accepted (value specified for the pd_max_act_guest_servers operand) does not exceed 34.
  • The unit is comprised of back-end servers only.
  • All servers within the unit belong to an HA group.
Effects on individual estimation formulas
If the value of the pdhagroup operand is changed, the following estimation formula is affected:
HiRDB Version 9 Installation and Design Guide:
  • Formulas for shared memory used by a unit controller under Estimating the memory size required for a HiRDB parallel server configuration