Communicating with data sharing groups

A data sharing group can be a powerful server in your client/server environment. The group can be part of a TCP/IP network, part of an SNA network, or part of a network that uses both protocols.

The group has a single-system image to requesting applications, whether requests arrive through TCP/IP or SNA. Queries can originate from any system or application that issues Structured Query Language (SQL) statements as a requester in the formats that are described by Distributed Relational Database Architecture™ (DRDA).

The distributed data facility (DDF) of DB2® uses TCP/IP and SNA to communicate with other DB2 subsystems. The DDF enables a DB2 subsystem to access data that is held by other database management systems. The DDF also enables the DB2 subsystem to make its own data accessible to other DB2 subsystems.

A data sharing group can support many more connections than a single member of the group can support. The DDF connections limit for a group is "n × 150,000", where n is the number of members in the group. Thus, a group with 16 members can support 2,400,000 DDF connections.

Ways to access data sharing groups
A requester is a client that manages connections and data access for client applications. Requesters can access data sharing groups in TCP/IP and SNA networks. Any product that supports the application requester protocols that are defined by DRDA can be a requester.
TCP/IP access methods
Together, TCP and IP use the client/server model of communication to enable communication between computers and computer networks of the same or different types.
SNA access methods
Systems Network Architecture (SNA) is a proprietary IBM® architecture that describes the logical structure, formats, protocols, and operational sequences for transmitting information units through, and controlling the configuration and operation of, networks.
Preventing a member from processing requests
Transparently to users, you can prevent one or more members of a data sharing group from handling DDF requests while still letting those members make DDF requests.
Update the BSDS with the DSNJU003 utility
DSNJU003 can be used to update the information stored in the bootstrap data sets of members of data sharing groups.

Parent topic: Introduction to DB2 data sharing

Related tasks:

Connecting distributed database systems