WebSphere eXtreme Scale Best Practices for Operation and Management

Chapter 3. Topology and infrastructure 33

separate JVM, often across a wire). The data that is stored in the grid is spread across the

JVM instances where WebSphere eXtreme Scale containers execute.

Figure 3-1 Distributed cache topology

A distributed topology is appropriate for most mission-critical enterprise web applications

where managing heavy loads with large data, achieving linear caching performance, and

executing large and complex application code are required. This topology provides fault

tolerance and high availability features. The operation of the application and its server has no

impact on the grid containers. The separation of JVM instances can help to avoid contention

of system resources and ensure replication performance and system response time.

3.2.1 Catalog service placement

The catalog service controls partition and shard placement and routing for all clients, making

it a critical component of the grid. As such, the catalog service must be clustered for high

availability and must be taken into account during the planning phase of the grid topology.

Unlike the WebSphere Application Server deployment manager, ensure that at least one

catalog server is up and functioning at all times; your grid is likely to become inaccessible if all

catalog servers are down.

ANY A PPLIC ATION J VM

Ap plica ti on

Stand-alone or managed

WebSphere eXtreme Scale

Container

Stand-alone or managed

WebSphere eXtreme Scale

Container

Partition

ANY APPLICATION JVM

Ap pl icat ion

Catal og service

Cat alog

Server

Catalog

Server

Cat alog

server

Gr id cl ie nt Gr id cli en t

EIS

Caution: Be aware that problems might occur if you have catalog servers or container

servers running in WebSphere Application Server processes with the same name. For

example, hosting a catalog service in more than one node agent, or if you have containers

running in servers with the same name on separate nodes (that is, server1). For more

information, see 5.1.6, “Duplicate server names in WebSphere Application Server” on

page 83.