Distributed System Members

Distributed system members are programs that connect to a Pivotal GemFire distributed system. You configure members to belong to a single distributed system, and you can optionally configure them to be clients or servers to members in other distributed systems, and to communicate with other distributed systems.

Distributed system members (or simply "members") connect to the GemFire system when they create the GemFire data cache. The members' distributed system is configured through GemFire properties. See gemfire.properties and gfsecurity.properties (GemFire Properties). GemFire properties specify all necessary information for system member startup, initialization, and communication.

Note: You cannot change a member's properties while the member is connected to the distributed system.
Use the properties to define:
  • How to find and communicate with other system members
  • How to perform logging and statistics activities
  • Licensing information for the system
  • What cache.xml file to use for cache and data region initialization
  • Other options, including event conflation, how to handle network loss, and security settings

Distributed System Membership and System Topologies

Every GemFire process is a member of a distributed system, even if the distributed system is defined as standalone, with just one member. You can run an individual distributed system in isolation or you can combine systems for vertical and horizontal scaling. See Topology and Communication General Concepts.
  • Peer-to-Peer Distributed Systems. Members that define the same member discovery properties belong to the same distributed system and are peers to one another.
  • Client/Server Installations. The client/server topology uses relationships that you configure between members of multiple distributed systems. You configure some or all of the peers in one distributed system to act as cache servers to clients connecting from outside the system. Each server can host many client processes, managing cache access for all in an efficient, vertically hierarchical cache configuration. You configure the client applications to connect to the servers, using a client cache configuration. Clients run as members of standalone GemFire distributed systems, with no peers, so all data updates and requests go to the servers.
  • Multi-site Installations. The multi-site topology uses relationships that you configure between members of multiple distributed systems. Through this configuration, you loosely couple two or more distributed systems for automated data distribution. This is usually done for sites at geographically separate locations. You configure a subset of peers in each distributed system site with gateway senders and/or gateway receivers to manage events that are distributed between the sites.