In this section, we will take you through a basic setup on a new system to explain how this works.
Example - Installing the environment
The environment we will use in this configuration consists out of 2 systems:
- dbvel71 - Primary Database Server running an 18c database called orcl
- dbvel72 - Standby Database Server that will be used as the Standby Database - Oracle 18c database software is installed and matches the Primary exactly.
- dbvel72 - Central Console and Observer system. This is where the Dbvserver (GUI) will be installed as well as the new Dbvisit Observer component.
Step 1: Installing the Dbvisit Standby Software on Primary and Standby.
This step should be familiar to most, if not please refer to the Install Dbvisit Standby section in the User guide
Step 2: Installing Dbvisit Observer
The next step is to install the Dbvisit Observer onto the 2nd Node dbvel72. This system will also run the Central Console (GUI) and the Dbvisit Observer component.
If you have followed the steps above you would now have the Dbvisit Standby GUI and Dbvisit Observer installed on the 2nd Node. In this example dbvel72
Step 3: Start the Observer component
The observer component must be started as a background process in Linux. In the below example we will show the options of Observer components and how to start it.
Step 4: Adding the Dbvisit Observer to the GUI
The next step once you have a standby database configured is to add the Observer to the Dbvisit Standby console.
This is done by navigating to the "Manage Configurations" menu option. From the Configuration page, click on "New" next to the "Add a Dbvisit Observer" section at the top as shown below:
There are three values required to add the observer to the Central Console:
The hostname or IP where the observer is configured
The port number on which the observer process is listening (Default is port 10853)
The observer passphrase - (default is admin900)
- Fill in the values as per below
1- the hostname - in this case, dbvel72
2- the port - which is the default 10853
3- the passphrase - admin900 (the default all lower case)
4- click on Save
Once the above is complete you will have the observer now listed in the Configuration Section as can be seen below:
You have the observer now configured, and added to the Dbvisit Standby Console. Remember: you can only have one Dbvisit Observer process per Central Console configuration.
Step 5: Adding a specific DDC to the Observer for monitoring
The next step is to enable the Dbvisit Observer to monitor a particular DDC.
This is done for each specific DDC and to enable this you can click on the "Monitor" icon under the Dbvisit Observer section - as highlighted in the section below:
Once you click on Monitor the following dialogue will be displayed:
This dialog will show you the basic settings you can configure:
1- The Poll Interval
This is in seconds and indicates how often the Dbvisit Observer should monitor the particular configuration.
NOTE: It is very important that this poll interval is always greater then your expected network delay/timeout. For example, if a connection to your Primary or Standby host fails, how long does it take to timeout and report an error? If this is 60 seconds (a common default network timeout setting), this poll interval should be set to at least 61 seconds.
Setting the poll interval to a value less than the expected network delay/timeout can result in various incorrect error states being reported by the Observer.
If you do not want to modify your network timeout settings, but still want to set the Observer poll interval to be less than the maximum expected values for these, you can do so by use of the advanced "remote_timeout" parameter - please refer to the Advanced Configuration Parameters section below.
The retry option is the number of times the Dbvisit Observer will monitor the particular DDC if a Failure is detected, Example, in the above the Observer will monitor the specific DDC configuration every 2 minutes (120 seconds), and if any errors are detected it will retry 5 times. After 5 errors (failures of the rules, more on this below), the "Operation mode" action will be executed.
3- Operation Mode
The operation mode is a very important setting - this is where you can select between two options:
"Manual Mode" - This is the default and puts the Dbvisit observer in what is called a "Dry Run" or Observe Only mode, meaning if a failure of the rules is triggered, Alerts will begin appearing in the GUI and Notifications will be sent out (configured under Advanced Settings) but the standby database is will NOT be activated. So no actual Automatic Failover is performed. It is highly recommended that this option be used for thorough testing in your configuration before you enable the "Failover Mode" - which if enabled will perform activation of the standby if the rule checks fail.
"Failover Mode" - This is the "real mode" of the Observer, where Automatic Failover (Activation) of the standby database will be performed if the rule checks fail the maximum specified number of times (as set in the Retries setting). For example, if the primary database goes down, and stays down for more than 10 minutes in this scenario (5x retries of 120 seconds each), the Failover will be triggered and the standby database will be activated. Note that Notifications will also be sent if enabled under the Advanced Settings section.
4- Log File Notification
By default as soon as you enable a DDC to be monitored by Dbvisit Observer, a log file will be created for any notifications specific to that configuration This log file is created on the node where the observer is running, which in this example is dbvlin03 and the location is: /usr/dbvisit/observer/log as we installed the Dbvisit Observer into the default DBVISIT_BASE location which is /usr/dbvisit. This setting cannot be disabled or modified. Note that this log will only contain DDC-specific entries, the same entries that would be sent out for any of the Notifications specified for the DDC in Advanced Settings. The full Observer log, including non-DDC-specific events, can be viewed in the Observer installation directory under /log/observersvc.log.
If you now click on SAVE SETTINGS, the default rule ("observer", specified on the Advanced Settings page, more on this below) will be applied, and monitoring of the DDC will begin.
The particular DDC - in this case, orcl - is now being monitored. The monitoring can be stopped at any time by selecting the "Stop Monitoring" option. You will also notice the Operating Mode which in this case is "Manual Mode" is displayed. This means that this configuration is only being monitored (Auto Failover if off), and if the connectivity checks fail, only notifications will be sent and the monitoring will be stopped. No Automatic Failover will happen, as in Manual Mode, the Dbvisit Observer is only, funnily enough, observing.
There are also the settings as shown above in point , which can be used to configure the monitoring for this DDC in more detail, such as enabling email notifications or changing the ruleset.
Step 6: Advanced Configuration
Once you click to edit settings for a particular DDC, you can navigate to the "Advanced Settings" section, from where you can configure the following:
- Email and Slack Notifications
- User Scripts (this can be a user shell script that is located in the DBVISIT_BASE/standby folder on both the primary and standby)
- Selecting the Rule Priority - default is "Observer", which means connectivity and database status checks only
We will now cover each of these in detail.
The observer installation is similar to the installation of the other dbvisit components in windows. Double click on the Installation executable and when you click Next you will see the options to install the Dbvisit components. You can see the option of the Observer as well [ 1].
Once the installation steps are completed, the observer service is started [2 ], you can check the service status from windows services [3 ].
The configuration is exactly the same as the Linux configuration and its done from the central console. Go to Manage Configurations page and click on New
- Enter the host in which Observer was installed.
- The default port for Observer is 10853
- The password is admin900
- Save the configuration
- Click on Monitor to configure the Observer and to start monitoring the Standby database.
The default configuration has poll interval as 120 and retries as 5 with Manual mode (this does not activate the standby)