OSI/MHS Configuration and Management Manual

Sizing and Tuning Your OSI/MHS Subsystem

OSI/MHS Configuration and Management Manual—424827-003

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Tuning OSI/MHS Attributes

The default values of OSI/MHS attributes normally provide satisfactory performance for

a medium-sized configuration. It is best not to modify values from their defaults unless

you recognize a problem and understand the implications of a change you are about to

make.

GI Class Attributes

For best performance results, use the defaults for the GI class attributes. For

descriptions of the GI class attributes, see the OSI/MHS SCF Reference Manual.

LO Class Attributes

For best performance results, use the defaults for the LO class attributes. For

descriptions of the LO class attributes, see the OSI/MHS SCF Reference Manual.

MR Class Attributes

The following types of MR class attributes have special impact on performance:

cleaner interval, number of associations, association control, recovery, CUG checking,

and route and link-retry control.

Cleaner Interval

Setting the cleaner interval to a short time means frequent sweeps through the PDU

stores (that is, a large number of reads); setting it to a long time means that PDU

stores will become full for an active system. A short time allowed for cleaning may

mean that a number of unnecessary reads will occur; a long cleaning time may mean

that other processes are delayed. Setting the store cleaner priority to less than MR

process and RTS priority ensures that the store cleaner runs as a background process.

You can set specific times of day for the store cleaner to run rather than specify an

interval.

Number of Associations

Setting the total number of associations allowed to a low number might lighten the load

on the RTS processes, but also keep other associations from being started, causing a

bottleneck for message delivery to other adjacent MTAs. If the number of associations

is large, other processes may be slowed down because of the amount of memory

required for each process.

Association Control

Association processing speed is affected by checkpoint and window size. Checkpoint

size is the amount of data transmitted before a session-layer minor synchronization

occurs. Window size relates to the amount of data transmitted before a session-layer