There are few scenarios where the operation team is handling so many components and, there is high chance of having difference in Software version, License, configuration details on the device running with High Availability within DC, DR and between DC and DR locations.
Following are the checklist we need to follow to keep the configuration, License, and Software Versions intact at both DC and DR devices and within DC and DR appliances.
1. Make Sure to run DC and DR units with same image version.
2. Make sure to check the license on both DC and DR appliance. Device must have permanent license installed and license feature must be same on all the DC and DR units.
3. Make sure to set the correct time on DC and DR appliance. All the devices must be enabled with NTP and get time from same NTP Server.
4. Make sure Cluster/HA status within DC and Within DR in Active-Standby mode.
5. Always remember to do a configuration on both DC and DR appliance.
6. Always remember to do a write memory or saving of configuration the appliance once any modifications are done.
7. Always remember to take full configuration backup (Includes SSL Key and certificate) and Technical statistics before you make any changes on the units also export the same to local machine.
8. Before doing any Drill activities, make sure the configuration is intact on the location where you are going to divert the traffic.
9. Have a practice of doing configuration synchronization when you make changes on one box either at DC or DR.
10. Have a practice of taking regular/ periodic full backup. May be weekly once or daily once or monthly once (provided changes are less).
11. Delete old backups from the device, if required download the old backups and save on local machine.
12. Give the device a proper meaningful hostname, this helps to identify the device when you have multiple devices in your network.
13. Please go through the release notes before OS upgrade the device.
14. Before doing any configuration try to understand the use the that particular configuration. Go through the CLI guide for information about any command.