Backup is governed by three vectors:
- RPO – Recover Point Objective, the amount of data that is lost when a backup is invoked (worst case a disaster and best case recovery from a log file),
- RTO – Recover Time Objective, the time it takes to restore the service and restore the application to full functionality,
- Backup Cost – the total cost of backup, including staffing, software and hardware.
In moving to a virtualized world, all these vectors can change. A virtualized server environment may be more efficient, but the lack of resources for backup and (usually more importantly) recovery will impact RPO and RTO. Data de-duplication may reduce cost and RTO but impact RPO.
With its first attempt at providing a backup and recovery infrastructure, VMware introduced VMware Consolidated Backup (VCB) and struck out by increasing all three vectors. For most virtual installations, backup and recovery were serious constraints on the deployment of virtualization, and a rip-and replace of the backup software infrastructure was a costly and risky alternative.
With the introduction of VMware APIs for Data Protection (VADP) and Change Block Tracking (CBT) VMware has scored a home run. The software backup industry has now can retrofit retrofit effective support for VMware environments to its traditional backup products. The current list of backup products that support VADP are:
- ArcServe from CA,
- Avamar from EMC,
- NetBackup & Backup Exec from Symantec,
- Simpana from Commvault,
- Tivoli Storage Manager from IBM (image backup still requires VCB),
- Veeam Backup from Veeam,
- vRanger from Visioncore.
VMware says that other vendors have product updates incorporating VADP in the pipeline for 2010 delivery.
However, significant redesign of backup and recovery procedures and backup software options together with testing will still be required to implement an effective solution that will meet current RPO and RTO objectives within the same cost envelope.
Action Item: CIOs and CTOs managing the migration to VMware should not rip and replace their existing backup software strategy unless their vendor has no plans to move to VADP and CBT. As and when there is good support for VADP and CBT, organizations should invest the resources to redesign their existing backup software design infrastructure and optimize it for VMware to ensure that the vectors or RPO, RTO, and cost are properly balanced.