My company is doing server OS upgrade, so as a tester I would want to know what types of testing is most helpful in this process?
Please run through below check list and pick applicable ones for your environment
- Regression Testing - Ensure Server, Features stable and running fine post upgrade
- For browser upgrades - Compatibility testing
- For specific machine upgrades (Not all machines upgraded) - If not all systems are upgraded then basic testing needs to ensure different versions of platforms do not have any impact. Connectivity of upstream and downstream system post upgrade is successful
- Monitor resource usage (CPU / DB) and measure if there is any abnormal spike. There could be override / change in default system param. This may hurt performance aspects
- In case of upgrade failure test the roll back strategy
- All this upgrade need to be done from QA-UAT finally to prod
- Managing downtime during the upgrade (Read only access / fail over systems ?)
Expecting you have a DTAP setup: Upgrade the Acceptance server OS and let any users depended on the services of the server accept that their applications are still working.
For operational testing have a look at what ITIL describes: http://wiki.en.it-processmaps.com/index.php/Service_Validation_and_Testing