294 IBM Content Manager OnDemand Guide
The z/OS Parallel Sysplex technology enables the Content Manager OnDemand servers to 
share configuration files, database, JES, HFS, and archive. For performance reasons, all HFS 
read/write directories that are used for temporary storage of data are configured as unique to 
each Content Manager OnDemand server. 
From a client perspective, the “cluster” is a single IP address. Incoming client requests are 
received by the sysplex distributor/Workload Manager (WLM). WLM monitors the various 
systems in the Parallel Sysplex and selects the appropriate Content Manager OnDemand 
server to forward the request to based on the current system workload and availability, so that 
the system that is more available (less busy) receives the request. 
12.3.3  High availability: IBM i
IBM PowerHA® SystemMirror® for i is the integrated IBM storage-based clustering solution 
for high availability and disaster recovery. The data and applications are deployed into storage 
pools, which are called independent auxiliary storage pools (IASPs). IASPs can be deployed 
by using either internal or external storage. At any time, the nodes in the cluster can switch 
roles and become either a primary or backup node. PowerHA SystemMirror can be used for 
on-demand role swap operations.
The IBM Power Systems™ Capacity BackUp (CBU) offerings support disaster recovery and 
high availability needs. The CBU offerings recognize that true high availability or disaster 
recovery solutions require at least two systems. If one system is not available, the other 
system takes over. The CBU offering provides flexible and economic options for deploying 
business continuity operations.
In a high availability environment on IBM i, you might not want to replicate the following 
directories because OnDemand places only temporary data in them, and this data might 
occupy a large amount of space:
/SM590000Do not replicate the temporary integrated file system (IFS) directories for your instances. 
For example, do not replicate /QIBM/UserData/OnDemand/QUSROND/TMP or 
/QIBM/UserData/OnDemand/QUSROND/PRTTMP, where QUSROND is your instance name.
/SM590000Do not replicate the home directory for the user that is storing data. For example, if 
JOHNDOE is the name of the user profile that stores data into Content Manager 
OnDemand, do no replicate /home/JOHNDOE.
/SM590000Do not replicate the /tmp directory.
12.3.4  Horizontal and vertical scalability summary
Y ou can use the architectural flexibility of Content Manager OnDemand (Figure 12-7 on 
page 295) to select the correctly sized system based on your needs. A Content Manager 
OnDemand implementation can be scaled both vertically (by using larger and larger systems) 
and horizontally (by increasing the number of systems that are part of the Content Manager 
OnDemand instance).