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

Maintaining a PATHMON Environment
HP NonStop TS/MP System Management Manual—541819-007
5-26
Understanding the Causes of Link Dissolution
your environment includes the Pathway/iTS product, the PATHMON process also
maintains status information for TCP and TERM objects.
By understanding how PATHMON manages links and what causes dissolution of links,
you can take steps to improve the performance of your system.
This can adversely affect PATHMON performance under exception conditions such as
network or processor failure:
•
Maintaining object status to manage links.
To manage links, the PATHMON process maintains status information about
PATHMON-controlled objects and LINKMON processes or ACS subsystem
processes. During exception conditions, managing communication between these
objects and server processes can slow the PATHMON process’ response time to
other commands (from PATHCOM or SPI).
•
Creating and deleting links.
If the PATHMON process is configured so that it is constantly creating and deleting
links, the server may wait for processor cycles, causing incoming transactions to
be placed on the server-class wait queue.
For more information about PATHMON performance and steps you can take to
improve it, see Managing PATHMON Process Performance on page 5-27.
Understanding the Causes of Link Dissolution
A PATHMON process, LINKMON, ACS subsystem processes, or TCP process, or a
server process (indirectly) can delete a link. This table describe how a link manager
can cause deletion of a link.
A link manager will return a link to a server process when any of these situations occur:
Cause Action
A “DELETEDELAY” timer expires for a dynamic
link.
Returns the dynamic link.
An OPEN error occurs on a link. Returns the link.
An I/O error occurs on a link. (I/O errors include
timeouts caused by the SET SERVER TIMEOUT
value. Timeouts caused by the
SERVERCLASS_SEND_ timeout value are not
considered to be link errors.)
Returns all links for this server process,
allowing current I/O to complete.
The PATHMON process sends a server class
stop request.
Returns all links for this server process,
allowing current I/O to complete.
The PATHMON process sends a forced delink
request.
Returns all links to the server process,
allowing current I/O to complete.