How Virtualisation Impacts Data Backup And Recovery

Introduction

Virtualisation brings many benefits, such as increased efficiency and flexibility. However, it also introduces new complexities when it comes to data protection. As a virtual infrastructure administrator, I need to understand how virtualisation impacts data backup and disaster recovery to ensure my organisation’s information is protected. In this article, I will provide an in-depth look at how virtualisation changes data backup and recovery approaches.

The Challenges of Backing Up Virtual Machines

Virtual machines (VMs) are abstraction layers on top of physical hardware. This provides great flexibility but also creates some unique data backup challenges:

• Increased data volumes – Each VM contains its own operating system, applications, and data. This leads to larger backup volumes compared to physical servers.

• Backing up shared data – Some data, like virtual hard disks, is shared between multiple VMs. Special care needs to be taken to back up this shared information.

• Application consistency – Applications and data within VMs need to be backed up in a consistent state. Most backup software provides application-consistent backups to address this.

• Lack of visibility – In large virtual environments, it can be difficult to keep track of all VMs and ensure they are successfully backed up.

To summarise, while VMs provide huge efficiency gains, their dynamic nature creates new difficulties for reliable data backup.

Backup Options for Virtual Infrastructures

Several approaches exist for backing up VMs, each with their own pros and cons:

Agent-Based Backups

• A backup agent is installed on each VM to be backed up. The agent communicates with backup software.

• Pros – Application consistent backups, easy to manage backups at VM level.

• Cons – Additional resource overhead to run agent in VM.

Agentless Backups

• VM datastores are backed up directly without agents.

• Pros – No resource overhead on VMs. Easier to scale to large environments.

• Cons – No application consistency. Limited granular control.

Image-Level Backups

• Entire VM disk files are backed up periodically.

• Pros – Simple, fast full VM backups. Application consistency.

• Cons – Large backup storage requirements. No incremental backups.

In summary, each backup method has advantages and disadvantages that need careful consideration when backing up virtualised systems.

Virtual Machine Recovery Considerations

Recovering failed VMs also has some specific considerations:

• Full VM recovery – Backups allow restoring a complete VM in case of failure. This is the simplest recovery approach.

• File-level recovery – Some backup solutions allow restoring individual files from VM backups. Useful for recovering specific lost files.

• Bare metal restores – Some backup applications can restore VM data to a physical server, helpful for VM-to-physical migrations.

• Partial restores – Block-level incremental backups can facilitate restoring only changed blocks, reducing recovery time.

• Multi-VM consistency – Multi-VM applications need to be recovered consistently to the same point-in-time to avoid data loss or corruption.

• Recovery automation – Scripting and automation helps scale and speed recovery of multiple VMs. Integration with virtualisation platforms like vSphere helps.

The ability to reliably recover VMs and data is critical for any virtual environment. Careful design is required to choose recovery approaches that match application needs.

Ensuring Availability and Business Continuity

Virtualisation facilitates high availability (HA) and disaster recovery (DR) capabilities:

• Clustering – Combining multiple ESXi hosts provides VM failover protection within a site.

• Replication – VM replicas enable recovery from site-wide outages. Backup copies can also serve as replicas.

• Backup storage policies – Backups should follow the 3-2-1 rule (3 copies, 2 media types, 1 offsite copy) to ensure availability.

• Orchestration – Automation and runbooks help orchestrate coordinated recovery across multiple systems.

• Testing – Regular failover/failback testing validates recovery plans. Missing dependencies can impact VM recovery if untested.

Proper backup and DR planning is key to providing business continuity for virtual workloads. New capabilities also introduce new failure scenarios to consider.

Conclusion

Virtualisation provides enormous efficiency and agility gains for modern IT environments. However, the abstraction layers also introduce new backup and recovery complexities. As a virtual infrastructure administrator, I need to leverage the right tools, recovery approaches, and availability capabilities to protect my organisation against data loss and downtime. With careful planning, virtualised workloads can be protected just as robustly as physical systems, while also gaining operational benefits.

Key Takeaways:

• Virtualisation introduces new data protection and recovery challenges like large data volumes, shared data, and lack of visibility.

• Multiple backup approaches exist including agent-based, agentless, and image-level methods, each with pros and cons.

• Recovering VMs has considerations like full vs file-level recovery, bare metal restores, and multi-VM consistency.

• High availability and disaster recovery capabilities help ensure virtualised application uptime and continuity.

• With the right tools, backup policies, and testing, virtualised systems can be protected effectively.