Pathway/XM System Management Manual

Managing Servers
Compaq NonStop™ Pathway/XM System Management Manual—426761-001
9-2
Distributed Server Classes
In the Pathway/XM environment, you manage SERVER objects by server class only;
Pathway/XM manages the individual server processes automatically on your behalf.
When you issue a START SERVER command, Pathway/XM performs the following
actions for each specified server class:
1. The link control service (LCS) process for a distributed server class, or the
PATHMON process for a direct or replicated server class, creates the server process
by calling the NEWPROCESS or PROCESS_CREATE_ procedure.
The server process context includes all DEFINEs specified in the server class
configuration (using the SET SERVER DEFINE statement).
2. The LCS or the PATHMON process opens the server, sends the server a startup
message, and then closes the server.
The startup message has a header that is constructed from what you specified for the
IN, OUT, and VOLUME attributes in the SET SERVER statement. If you specified
a character string for the STARTUP attribute, that is also included.
3. If the server replies with a value of 70 (FECONTINUE) to the startup message, the
PATHMON process sends variables and parameter messages to the server.
The ASSIGN messages are constructed directly from the information you provided for
the ASSIGN attribute to the SET SERVER statement. The PARAM message contains
one item for each attribute value you specified for the PARAM attribute of the SET
SERVER statement.
When starting a direct or replicated server class, the PATHMON process repeats the
server startup operations for the total number of static server processes defined by the
SET SERVER NUMSTATIC attribute.
Distributed Server Classes
When a server class of type DISTRIBUTED is started, one link control service (LCS)
process is created for each PATHMON process associated with the server class.
If the configured value of the NUMSTATIC attribute for the server class is greater than
zero, the LCS then the number of server processes specified for NUMSTATIC. The
server processes are distributed evenly among all the PATHMON processes; if
necessary, the value of NUMSTATIC is adjusted upward to provide the same number of
server processes for each PATHMON process.
In a distributed server class, all the server processes (except this first one) are dynamic;
that is, they are created as needed in response to transaction requests. As transaction
requests for the server class are received from TCPs and LINKMON processes, they are
handled by the LCS process, which creates additional server processes as needed based
on process reservations from the process broker (PB) process.
Note. To start a server process that has been frozen (with the FREEZE command) and then
stopped, you must first issue the THAW command. For more information, see Freezing and
Thawing Server Classes on page 9-4.