Any time that the GCM server is started using the normal startup
procedure, it is running in a mode that supports automatic restart
behavior. When run in its normal mode, the GCM server produces its
run-time log file, but offers little additional information for
troubleshooting possible GCM server problems.
The following sections contain information to assist you in
troubleshooting possible GCM server problems.
Obtaining Diagnostic
Information At times it may be beneficial to run the GCM server in a mode
that allows some diagnosis to occur. Diagnostics produce procedural
trace information that is either written to the GCM server event
log, if enabled, or output to the screen, if enabled. Typically,
diagnostic output is directed to the screen; however, the event
log output is useful if you need to forward it to HP support personnel
for help.
To get diagnostic screen output from the GCM server, you must
run the GCM server interactively rather than as a detached process.
To do this, stop the GCM server if it is currently running, and
restart it from a DECterm window by entering the following command:
$ RUN SYS$SYSTEM:GCM_SERVER.EXE
Once the GCM server is running, connect to it from a GCM client
with administrative privileges, and edit the GCM administration
database as follows:
Select Edit Admin
Database from the File menu.
Select the Server Init page.
Locate the Diagnostic text field and note the buttons
for selecting the desired output.
Click the Screen output button and enter the appropriate
diagnostic code or codes, according to the following table. You
can set more than one flag at a time.
Code (decimal)
Code (hex)
Function
Action
0
0
DIAGNOSTIC_DISABLE
Disables diagnostics.
1
1
HEARTBEAT_TRACE
Servers disconnecting.
2
2
TRANSACTION_TRACE
General troubleshooting.
4
4
XML_TRACE
General troubleshooting.
8
8
LOCK_TRACE
Server hangs.
16
10
COMMAND_TRACE
Disables execution and dumps
packet.
32
20
CRYPTO_DISABLE
GCM administration database troubleshooting.
By default, regardless of whether the GCM client-server
communications is using security (SSL), the GCM administration database
is always encrypted. On rare occasions, you may want to disable
encryption of the GCM administration database GCM administration
database file. By setting the CRYPTO_DISABLE flag, GCM servers will
no longer encrypt and update the GCM_ADMIN.EDB file. Instead, they
will output plain ASCII XML to GCM_ADMIN.DAT, and will accept input
on startup from GCM_ADMIN.DAT. This allows you to directly edit
the XML structures within the GCM administration database and to
review modifications made by the GCM client and server.
Run the GCM servers with the CRYPTO_DISABLE flag set
only for troubleshooting because running the servers with this flag
set exposes GCM user authorization records in simple ASCII unencrypted
form.
Remember to disable diagnostics before returning a GCM server
to service. If you do not disable logging, the related GCM server
log files can grow very large and GCM server performance will suffer.
Potential Problem
Areas Heartbeats are a potential problem area for heavily loaded
systems. For GCM servers to detect the presence and loss of GCM
clients and GCM servers in other instances, periodic heartbeat transactions
are issued. The GCM server is smart enough to optimize the heartbeat
process, altering the rate based upon usage, and requiring only
one-way heartbeats. At times, GCM server or network activity delays
the issuance of a heartbeat. The GCM server is designed to tolerate
a number of missed heartbeats before assuming disconnection.
You can tune heartbeat values to suit specific needs by using
the GCM client to edit the GCM administration database. Three values
apply: the Client Pulse, Server Pulse, and Flat Line. The Pulse
values are the number of seconds between heartbeat transactions.
The Flat Line value is how many heartbeats can be missed before disconnection.
These are preset to values that yield good behavior without undue
traffic. Under special circumstances, you can alter these values
if you find your sessions are being disconnected. These values have no
effect on the overall responsiveness of the GCM with regard to command
and event processing.
Timeout Detection The GCM client contains a debug hook to turn off timeout detection
entirely. To enter a debug mode, press Ctrl+Alt+D+B. A TEST menu
item indicates this mode is active. In this mode the GCM client
remains connected regardless of how long it takes to get a response
back from a slow GCM server (such as one that is being debugged).