3.3.2 Modifying the GROUPS Section

The parameters in the GROUPS section implement two important aspects of distributed transaction processing:

• They associate a group of servers with a particular LMID and a particular instance of a resource manager.
• By allowing a second LMID to be associated with the server group, they name an alternate machine to which a group of servers can be migrated if the MIGRATE option is specified.

The following table describes the parameters in the GROUPS section.

Table 3-2 Parameters Specified in the GROUPS Section

Parameter	Meaning
LMID	LMID must be assigned in the MACHINES section to indicate that this server group runs on this particular machine. A second LMID value can be specified (separated from the first by a comma) to name an alternate machine to which this server group can be migrated if the MIGRATE option has been specified. Servers in the group must specify RESTART=Y to migrate.
GRPNO	Associates a numeric group number with this server group. The number must be greater than zero (0) and less than 30000. It must be unique among entries in the GROUPS section in this configuration file. (Required)
TMSNAME	Specifies which transaction management server (TMS) must be associated with this server group.
TMSCOUNT	Specifies how many copies of TMSNAME must be started for this server group. The minimum value is 2. If not specified, the default is 3. All TMSNAME servers started for a server group are automatically set up in an MSSQ set. (Optional)
OPENINFO	Specifies information needed to open a particular instance of a particular resource manager, or it indicates that such information is not required for this server group. When a resource manager is named in the OPENINFO parameter, information such as the name of the database and the access mode is included. The entire value string must be enclosed in double quotes and must not be more than 256 characters. The format of the OPENINFO string is dependent on the requirements of the vendor providing the underlying resource manager. The string required by the vendor must be prefixed with rm_name:, which is the published name of the vendor's transaction (XA) interface followed immediately by a colon (:). The OPENINFO parameter is ignored if TMSNAME is not set or is set to TMS. If TMSNAME is set but the OPENINFO string is set to the null string ("") or if this parameter does not appear on the entry, it means that a resource manager exists for the group but does not require any information for executing an open operation.
CLOSEINFO	Specifies information the resource manager needs when closing a database. The parameter can be omitted or the null string can be specified. The default is the null string.