What you need to know about backing up virtual machines

The benefits of using virtualization to consolidate data center infrastructure and provide a more flexible platform for moving, provisioning and backing up workloads are proving alluring to companies of all sizes. However, while virtualization can bring considerable value to organizations in terms of improved server resource utilization it is important to understand the implications of moving to a virtual environment when it comes to protecting the infrastructure.

Virtualization consolidates server estates into a common platform, where a single virtual host can contain several virtual machines. By doing this it introduces a single point of failure over multiple workloads. If a virtual environment is compromised it is likely to affect more server resources than in a physical world. Consider what would happen to a virtual infrastructure in the event of a connectivity outage to the primary storage unit? The entire virtual host would become unavailable and that can put upwards of 8-10 production workloads at risk.

As such, backup and recovery of virtual systems is a factor that has to be incorporated into the design and deployment of any virtualization project. It is important to not only protect the individual virtual machines but the entire virtual host.

Even before the adoption of virtualisation, backups could be configured to backup pieces of an application, data or the operating system of a server. The same approach can be applied to virtual workloads as they contain the operating system, application and usually the associated data as well. When a physical server is converted through the P2V process a virtual disk image (VMDK or VHD) is created which is used to spin up that workload as a virtual machine. So, for each virtual machine there is a corresponding virtual disk image that needs to be protected. However, backing up virtual machines is only one part of the process, having the ability to quickly recover them is just as important.

Virtualization has actually simplified the backup and recovery process as you only need to backup the virtual disk image to be able to restore as a whole versus trying to backup and recover bits and pieces of a server. Another advantage is that IT managers can usually restore that disk image to different hardware if necessary or an entirely different virtual host server.

This is where workload portability solutions have developed to easily move virtual workloads between virtual hosts for high availability. Products like VMware vMotion, Microsoft Live Migration provide the ability to transfer workloads in real-time between similar virtual platforms and other products provide the ability to move virtual workloads between any virtual platforms. VMware vMotion utilizes the replication functionality of the attached storage to replicate the virtual disk images between devices while Microsoft Live Migration is built upon failover clustering technology that allows shared storage between the virtual hosts. Other products can be more hardware and virtual vendor neutral, allowing virtual workloads to be moved in real-time across any hardware or virtual platform. All of these solutions can form the basis for effective backup solutions that can easily transfer the entire virtual disk image to another server and spin up quickly to minimize any interruption to production operations.

The processes used to backup virtual machines can be used the same as they were for physical servers and are basically broken down into hardware-based replication and host based replication. Tape backup solutions aren’t addressed in this article as they have become more of an archive option and don’t meet RTO or RPO requirements necessary for virtual infrastructure. However, once the virtual disk images have been replicated to a designated backup, tape is often used to archive those disk images to meet certain industry regulatory compliance.

In summary, no matter which virtualization product you select, make sure you think about protecting those servers on top of just converting to a virtual environment. Selecting a flexible data backup and recovery solution will not only help provide high availability but it can also help data centre managers better maintain these systems by having the ability to provision, convert and move the systems near or far. This provides more options for deploying virtual environments, managing them on a daily basis and enabling a better backup and recovery strategy.




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