To create a reliable infrastructure, adding your VMs to an Availability Set is key. Several scenarios can have an impact on the availability of your Azure VMs. These are as follows:
- Unplanned hardware maintenance event: When hardware is about to fail, Azure fires an unplanned hardware maintenance event. Live migration technology is used, which predicts the failure and then moves the VM, the network connections, memory, and storage to different physical machines, without disconnecting the client. When your VM is moved, the performance is reduced for a short time because the VM is paused for 30 seconds. Network connections, memory, and open files are still preserved.
- Unexpected downtime: The VM is down when this event occurs because Azure needs to heal your VM inside the same data center. A hardware or physical infrastructure failure often causes this event to happen.
- Planned hardware maintenance event: This type of event is a periodic update from Microsoft...
