Cluster limits

This topic provides system limits for clusters which include cluster software limits, OptiConnect limits, HSL OptiConnect loop limits, and SPD OptiConnect limits.

Table 1. Cluster software limits
Cluster software limits Value
Start of changeMaximum number of nodes in a clusterEnd of change Start of change128End of change
Maximum number of nodes in a recovery domain in a cluster resource group 128
Maximum number of clusters that a node may be a member of 1
Maximum number of IP addresses per cluster node 2
Maximum number of data port IP addresses per recovery domain node 4
Start of changeMaximum number of site names per device cluster resource groupEnd of change Start of change2End of change
Maximum number of configuration objects per cluster resource group 256
Maximum number of application restarts 3
Maximum number of nodes which can be configured in a cluster via the iSeries™ Navigator Simple Cluster Management interface 4
Table 2. OptiConnect (Option 23 of i5/OS™) limits
OptiConnect limits Value
Maximum number of systems that can be connected using OptiConnect 64
Maximum number of logical connection paths that can be established between two systems using OptiConnect 1 Start of change16End of change
Start of changeMaximum number of OptiConnect open connections between any two systems using OptiConnect 2End of change 16 382
Start of changeMaximum total number of active jobs on a system that can use OptiConnect 2End of change 262 135
Maximum number of TCP/IP subnets per system that can be configured to use OptiConnect3 8
Notes®:
  1. Start of changeOnly 2 of the 16 logical connection paths can be using SPD Bus adapters (others must be HSL).End of change
  2. Start of changeAn OptiConnect open connection is an active communications link between a job or task on one system and a job or task on another system. Using the WRKOPCACT command, you can determine the number of current open connections by adding the 'Users' count under the 'Client Statistics View' to the 'Agents' count under the 'Server Statistics View'. With this command, you can view the jobs and tasks associated with individual OptiConnect open connections by selecting F14 (Jobs and Tasks). End of change
  3. The following count as TCP/IP subnets:
    • Each OptiConnect TCP/IP interface with no associated local interface (ADDTCPIFC keyword LCLIFC(*NONE))
    • Each unique interface associated with an OptiConnect TCP/IP interface
Table 3. HSL OptiConnect Loop limits
HSL OptiConnect Loop limits Value
Maximum number of HSL OptiConnect Loops on a system Start of changeSee IBM®
eServer logo
i5 and iSeries Handbook. 2End of change
Maximum number of systems that can be connected on a single HSL OptiConnect Loop 1 3
Maximum number of I/O towers and IXA cards on a single HSL OptiConnect Loop 1 4
Maximum HSL cable length 250 meters (optical), 15 meters (copper)
Note:
  1. If more than two systems are on an HSL OptiConnect Loop, then no I/O towers or IXA cards are allowed on the same loop.
  2. Start of changeYou can also review the Start of changeHigh Availability and ClustersEnd of change web site for more information about designing a high availability solution.End of change
Table 4. SPD OptiConnect limits. Use this table to learn about SPD OptiConnect system limits.
SPD OptiConnect limits Value
Maximum number of systems per hub 14
Maximum SPD cable length 500 meters (1063 Mbps) or 2 kilometers (266 Mbps)
Parent topic: Maximum capacities