OSI/FTAM Programming Guide

FTAM Application Management
HP NonStop OSI/FTAM Programming Guide—528612-001
6-2
Capacity
Capacity
FTAM initiator capacity is determined by at least three factors: the number of
concurrent associations per process, the number of initiator processes running, and
the PDU size.
Multiple Associations
An FTAM initiator process can handle up to 32 concurrent associations; depending on
the workload of your application, you might want to set a lower limit. To set the
maximum number of associations per process, use the SCF ADD PROCESS and
ALTER PROCESS commands to configure the MAXASSOC attribute.
Each association is independent of other associations. You can create multiple initiator
processes to service one application. Thus, you can increase the total number of
associations your application supports, or spread the same number of associations
across several processes to increase throughput.
Multiple Processes
You can create up to 128 initiator processes to operate concurrently. Each new
process can be identical to the original process, but functions independently from any
other process. As stated above, you can use multiple processes either to support more
associations or to spread the workload of managing associations.
If there are multiple initiator processes in your configuration, the APLMGR process
uses a round-robin algorithm to assign associations to initiator processes. The effect is
that the number of associations is evenly spread among the initiators. (Whether the
workload is evenly spread or not depends on how much work your application requests
within the scope of each association.)
If the demand for associations is such that more than 128 initiator processes are
needed, you can also configure the system with multiple APLMGR processes, each of
which can handle up to 128 initiator processes.
Use the SCF ALTER SUBSYS command to set the maximum number of FTAM
initiators. To achieve the best throughput, have initiator processes run in different
CPUs. Use the SCF ADD PROCESS or ALTER PROCESS command to set the CPU
number. (Note that APLMGR never implicitly creates a new initiator process. You must
specify each process explicitly to SCF.)
Note. Whether you achieve the best throughput with a small number of initiators, each
handling many associations, or with many initiators, each handling a small number of
associations, depends on the application—for instance, on the volume of work performed
within each association, whether requests are fairly continuous or intermittent, and how these
characteristics vary during peak processing periods.