How can you ensure proper backup and restoration of virtual machines in case of failure?

1 Types of backups

When it comes to backing up your VMs, there are several options available depending on your needs and preferences. A full backup is a complete copy of the entire VM, including the operating system, applications, data, and settings, providing the highest level of protection but consuming the most storage space and time. Alternatively, an incremental backup is a partial copy of the VM that only includes changes made since the last backup; while a differential backup is a partial copy that only includes changes made since the last full backup. Both incremental and differential backups require less storage space and time than full backups, but incremental backups depend on the previous backups for restoration.

2 Backup tools

When it comes to backing up your VMs, there are various tools you can use, depending on the virtualization platform and the backup type. Native tools, such as VMware vSphere Data Protection, Hyper-V Backup, or KVM Backup, are built-in or provided by the virtualization platform and usually offer basic backup and restoration features like scheduling, compression, encryption, and deduplication. Third-party tools, such as Veeam Backup and Replication, Acronis Cyber Backup, or Zerto Virtual Replication, are developed by external vendors and generally provide more advanced features like replication, migration, verification, and recovery testing.

3 Backup frequency

When determining the frequency of backup for your VMs, you need to consider several factors, such as the criticality of the VM, the change rate of the VM, the recovery point objective (RPO), and the backup window. The more critical the VM is for your business or operations, the more frequently you should backup it. Similarly, if the VM changes more often, a higher backup frequency is needed. The RPO is also an important factor; a lower RPO requires a higher backup frequency. Lastly, if you have a shorter backup window, you need to reduce the backup frequency to avoid affecting performance or availability.

4 Backup location

When deciding where to locate your VMs' backup, it's important to consider the security, accessibility, and cost of your backup data. Your main options include local storage, which is attached to the same physical server or cluster as the VMs and offers the fastest and easiest backup and restoration; remote storage, located on a different physical server or cluster either on-premise or off-premise, which provides more protection and redundancy for the backup data; and cloud storage, provided by a cloud service provider such as AWS, Azure, or Google Cloud, which offers scalability and flexibility but involves more cost and complexity.

5 Restoration methods

The last element of backup and restoration of VMs to consider is the restoration methods. These determine how you can recover your VMs from the backup data in case of failure. Full restoration is the most comprehensive option, but it also takes the longest time and requires the most storage space. Partial restoration offers more flexibility and efficiency, but requires more expertise and compatibility. Finally, instant restoration is the fastest and easiest recovery, although it has some limitations and risks such as performance degradation or data corruption.