Users Guide

Cluster Constraints | Clustering
OMNM 6.5.3 Installation Guide 109
copied to the disaster recovery standby system on Real-time or on regularly scheduled
intervals(Database Dump). Application servers can be replicated by software like VEEAM, Avamar etc.
database Server to be replicated by oracle data guard(Real-time) or MySQL Replication(Real-time)
• All cluster members must run the same version of the application and listen on the same port.
NOTE:
The heartbeat between mediation and application servers now contains the software version
information. If the versions do not match, then OpenManage Network Manager generates an event/
alarm to indicate the issue.
• You must identically configure all servers running Enterprise JavaBeans (EJBs) with Java
Database Connectivity (JDBC) connection pools.
• For clusters using database connection pools, each cluster member must have an identical
connection pool. See
Database Connections on page 110 for more details.
• The Access Control Lists (ACLs) and servlets must be identical for every machine serving
servlets.
• All cluster members must have identical service configurations. You cannot, for example, turn
on mediation services in some cluster application servers and not others.
• Support exists for only a single application server cluster per system, but you can have several
mediation server clusters.
• Database servers can always be separate, no matter how you configure the other machines.
You can make a database machine part of an application server cluster/partition, but this is
not recommended.
NOTE:
For non-embedded database installations (Oracle) best practice is keeping the database server(s)
separate from the other machines.
• Although application servers process more than just mediation, any application server can also
run mediation services. Stand-alone mediation servers themselves run
only mediation
services. You can also turn mediation on and off on any host running an application server.
If you cluster application servers, one or more distributed mediation servers typically handle
mediation, and the clustered application servers have mediation turned off.
As stated above, you can also run both the application server and mediation services on a
single machine. A cluster of such combined application / mediation machines is also
possible—minimally two servers each running an application server with mediation services.
One caveat: Mediation processes have an impact on application server performance. This is
why best practice for larger deployments is to distribute mediation services to dedicated
mediation servers. Once you distribute mediation, you can ensure better performance by
disabling mediation on application servers in the application server cluster.
• SNMP Mediation agents can back each other up as primary/secondary for any subnet (any
range of IP addresses). A mediation agent which is primary for one subnet can be secondary
for a different one. Such subnets may not overlap.