Both are availability settings.
It ensures availability of virtual machines during unforeseen situations or during upgrades.
Fault domain:
It ensures availability of virtual machines during unforeseen situations or during upgrades.
Fault domain:
- Fault domain is racks of computers.
- Set of hardware components that share a single point of failure
- In a data center, rack of computers can be fault domain, which might be sharing same power source or network connection
- To minimize impact of possible hardware failure, Microsoft Azure deploys instances to at least 2 or more fault domains
Update domain:
- Upgrade domain keep your application running during upgrades
- Take down instances one by one, so that at any given time at least one running instance serving request
- There will be 5 upgrade domains by default, it can increase up to 21
Conclusion
- Fault domain - for unplanned failures
- Update domain - for planned maintenance operations
References:
