TS/MP System Management Manual (H06.05+, J06.03+)

Configuring Objects in a PATHMON Environment
HP NonStop TS/MP System Management Manual—541819-007
3-24
Links and Link Attributes
steps for each server class in your application, then add the totals to determine global
limits for such attributes as MAXSERVERPROCESSES.
Note that although the calculations and formulas that follow are intended to assist you
in arriving at an optimum configuration, they are necessarily generic. Only you know
the specific characteristics of your system. A good, general rule to bear in mind while
utilizing these formulas is that you will pay a small penalty—in unused resources—if
you overconfigure your system. On the other hand, you will pay a large penalty—in
performance and operations problems and obscure system errors— if you
underconfigure your system.
Links and Link Attributes
A link is a connection between a link manager, such as the LINKMON process or the
ACS subsystem processes, and a specific server process. The link is used to send a
request to, and receive a reply from, a server.
LINKMON or ACS subsystem processes share a link among the multiple Pathsend
processes executing in the processor of the LINKMON process or the ACS subsystem
processes. Only one Pathsend process at a time can use the link (for example, by
calling the SERVERCLASS_SEND_ procedure).
A link manager attempts to use one of its existing links to satisfy a send request. If no
such link is available, then the link manager does one of these:
•
If the link manager can get a static link, it asks for a link immediately.
•
If the process cannot get a static link, and no links become available in the period
of time specified in the CREATEDELAY parameter, then the link manager asks for
a link to a dynamic server process. Dynamic server processes are temporary
processes that the PATHMON process starts as needed and that run only as long
as the TCPs or LINKMON processes or ACS subsystem processes require them.
The PATHMON process will use all existing server processess (both static and
dynamic) before starting another server process. First, all links for the static server
processes are allocated. Then for each dynamic server process, all links available to
the server process (indicated by MAXLINKS) are granted prior to starting another
server process. This can lead to contention for the dynamic server process.
If there are insufficient links available, the PATHMON process generates a LINK
DENIED message to the log file (for the first occurrence of this problem).
You can change the number of links by changing the server class attribute MAXLINKS
or, preferably, you can add static servers. It is recommended that you configure for
enough static servers so that your application will need to employ few, if any, dynamic
servers.
At startup time, to ensure that all static servers are started and, consequently, links are
evenly spread, issue a START SERVER * command prior to starting any Pathsend
processes or, if you use Pathway/iTS, any TERM objects.
To specify information about links, use these attributes of the SET SERVER command: