Backing Up Virtual Machines

Backing Up Virtual Machines

By Chris Brunau

Virtualization software, known as a hypervisor, allows multiple “virtual” servers to run on a single physical server. It was designed to make better use of server hardware, by allowing multiple applications to be run on a single server. A virtual machine is a fully operational and isolated server, including OS, an application, and data, running on a physical server, typically alongside other virtual machines.

Some common examples of virtual machines include VirtualBox, ESX (VMWare), Oracle VM Server, Xen (Citrix), Hyper-V (Microsoft).

How Do I Back Up My Virtual Machine?

There are two main ways to backup virtual machines.

  • Agent-based backup: Agent-based backup products require the user to install a lightweight piece of software on each machine they want to protect. Agent software lives at the kernel level in a protected system so it can easily detect block-level changes on the machine. It doesn't need to scan the entire file system to determine changes for incremental backups. Agent-based can be more efficient than agentless for physical machines. On the other hand, agent-based backups rely on local compute resources to perform the backup and send it to the backup target. Therefore, the backup process can impact application performance if the protected server doesn’t have the computing power necessary to perform backups alongside production workloads. Generally speaking, this isn’t a big issue as long as the server is right-sized to handle necessary tasks. The agent tracks changes to the VM’s dataset which are copied to the backup device on a set schedule. Agent-based backup of VMs is perfectly acceptable for many organizations, however, two potential challenges emerge at scale. First, VMs can be spun up and decommissioned very easily. Backup agents must be manually installed on new VMs—if this doesn’t happen, these machines go unprotected. As businesses grow, this becomes more challenging to manage. Second, many backup software vendors use per-agent pricing. So, as organizations deploy more VMs, the cost to protect them also rises.
  • Agentless Backup: Agentless backup doesn’t require users to install agents on protected servers, therefore making it slightly easier to deploy and monitor. This is particularly important in virtual environments with many production machines, VMs can be spun up so easily it’s common for them to go unprotected when using agent-based backup because a backup agent is never installed. With agentless, this isn’t an issue. Many agentless backup products, for physical production machines, must inject temporary executable modules into systems before the backup can occur. For the most part, this isn’t an issue, especially if the application is backed up offers an API for the backup software to interface with. However, there is a chance that temporarily injected modules can create data integrity issues on protected machines. Where agentless backup procedures really shine is VM infrastructure. A good agentless backup software uses the Change Block Tracking (CBT) that exists with the Hypervisor. You get more benefits using agentless backups with a virtual storage location that understands how to transmit data from the hypervisor to the data store without using networking traffic. Therefore, you don't have to use IOPS on the local VM or use network bandwidth that would be better used for actual production processes. Agentless backup doesn’t require users to install agents on protected servers, preventing potential data loss. Depending on the backup software vendor’s pricing model, agentless backups can be less expensive as well, since users don’t need to pay licensing fees on a per-agent basis.

How to Back Up a Virtual Machine with a SIRIS

Datto Instant Virtualization allows a protected system to be virtualized and hosted either locally on a Datto BCDR appliance (SIRIS), or remotely in the secure Datto Cloud (Datto SIRIS and Datto ALTO) in seconds.

Regardless of whether the recovery point is months or even years old, Datto’s DRaaS solutions end the long RTOs caused by reconstructing backups on disk or restoring from magnetic tape. When virtualizing a recovery point, Datto’s advanced web interface allows for the configuration of CPU and memory resources. Network resources can also be configured dynamically, allowing for changes to be made without restarting the virtual machine. While virtualized, backup clients can continue a normal backup schedule. Business continuity has never been as easy or as reliable.

With Datto SIRIS, MSPs have an all-in-one business continuity solution. SIRIS is a reliable, solution built for MSPs to efficiently prevent data loss and minimize downtime for their customers. SIRIS includes verified backups, restore options for any scenario, instant virtualization, and ransomware protection. Learn more today.

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