Chapter 12: Server Monitor

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Purpose

Server Monitor is an interactive program used by system administrators to monitor the behavior of POMS servers. It can be used to monitor application servers as well as proxy servers. A system administrator can run Monitor on their desktop and refer to it to do a variety of tasks, including: A single instance of Monitor can be used to simultaneously monitor multiple servers.


Login

When you run Monitor, the following login window appears.

Unlike POMS, Monitor does not require you to have a user account to access it. Your network user ID is recorded as your implicit username. For password, you can use one of two generic passwords:

Enter your password and press Login.

If you change the passwords and forget them, you can restore the default passwords by deleting the file <root>/prag/monitor/password.txt in your server installation.


Main Window

After successful login, Monitor's main window appears.

A toolbar of buttons appears at the top of the window. For each monitored server, a tab appears below this toolbar, bearing the name of the server in this format: HostName:PortNumber (x Sessions). If a server is currently being monitored, then a green tick appears on the tab. When you temporarily suspend the monitoring of a server, the tick changes to a cross.

Each server tab in turn contains a number of other tabs which provide information on various aspects of the server.

At least one server tab will be present when you run Monitor. This will be the server against which Monitor is booted (this tab is not suspendable).

Servers

To add a server to the list of servers being monitored, press the Add Server button. The following dialog appears.

Enter the server address in the Server Host field, in the format HostName:PortNumber. For a secure server (i.e., a server deployed using SSL), make sure that the Use SSL checkbox is ticked. If you tick the Reconnect Next Time Running Monitor check box, a subsequent run of Monitor will remember this server and automatically add it to the list.

Once you press OK, Monitor will contact the server and, if successful, will add a tab for it to the main window.

To suspend the currently-selected server tab, press the Suspend button. This will stop the server from being monitored, but will not affect the server itself.

To remove the currently-selected server tab, press the Remove Server button. The server tab will disappear, but the server itself will not be affected.

To disable user login to the currently-selected server tab, press the Disable Login button. The button will change to Enable Login, and pressing it again will re-enable user login.

You can broadcast a message to all connected users by pressing the Broadcast button. The following dialog appears.

The two radio buttons at the top of the dialog give you the option of either sending a message to the users of the currently-selected server tab, or to users of all server tabs. Type in your message and press the Broadcast button.

These two features are useful when you want to bring down a server for maintenance. First, you should disable user login to that server, and then broadcast a message to the users of that server, warning them that the server will go down at a given time, and that they should save their work and logout.

A POMS server can be patched on the fly, without bringing it down. Patches that require a change to the server profile, require a server reset. You can do this by pressing the Reset Server button. Resetting a server does not affect any of its sessions. Therefore, users will not even know. Under normal circumstances, you should not have to use this command.

You can clear a server's database pools by pressing the Clear DB Pools button. Again, this will not affect server sessions and will be transparent to the users. This command is only useful in exceptional circumstances where a database pool has not properly released its memory.

Options

When you choose the Options command from the File menu, the following dialog appears.

The Heartbeat field specify the server polling frequency (defaults to 10 seconds). The Text Editor field specifies the path to the executable for a text editor to be used by Monitor for opening text files. The Diff Utility field specifies the path to the executable for a diff utility to be used by Monitor for comparing text files.

If you don't have a diff utility, we recommend WinMerge. This is an excellent open source diff utility, and can be downloaded from http://winmerge.sourceforge.net.

Change Password

To change the password for Monitor, choose the Change Password command from the File menu. The following dialog appears.

Complete the fields, and press the OK button. This will change the password you've logged-in with (e.g., if you logged in using the view-only password, it will change only that password).


Sessions

The Session tab plots the number of active sessions against time.


Users

The Users tab displays the list of active user sessions for the server.

The list of sessions can be refreshed by pressing the Refresh button. To terminate a session, select it and press the Kill button. To enable/disable the debug flag for a session, select it and press the Toggle Debug button. This will cause the session to write each request and its result to the server log. To view the stack trace for a session, select it and press the Session Stack button. The stack is displayed in the lower half of the tab. To view the stack trace for all sessions, press the All Session Stacks button.


Memory

The Memory tab plots the amount of server memory allocated and used against time.


Response

The Response tab plots the average server latency against time.


Server Log

The Server Log tab displays the server log. Server activities, warnings, and errors are written to this log.

Depending on how the server is setup, the log file may be cut off at certain points in time. The log file is also cut off when you do a Server Reset. The historical log files can be accessed and viewed via the File Exchange tab. They are stored in the directory <root>/log/.


File Exchange

The File Exchange tab allows you to copy files/directories between your local machine (on which Monitor is running) and the remote (server) machines. The left panel represents the local machine, and the right panel the remote machine.

You can do the following on local/remote sides:


Reports

The Reports tab allows you to run a predefined report against the server.

To run a report, select its name from the Report drop-down list. The From and To fields are relevant to some reports, and limit the scope of the report to the data falling within the specified dates.

Press Generate to generate the report. The report result is displayed in the panel below the button. Some reports write their result to a file, in which case, the file will be automatically opened.


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