On to two more backup mistakes in virtual environments that are all-to-common among IT professionals. If the first five mistakes listed earlier (Part 1, Part 2, Part 3) weren’t enough to convince you that backing up virtual environments is a challenge, here are two more.
Mistake #6: Backing Up to Tape-only (or Disk-only)
Some IT professionals still take a singular approach and use only disk or only tape. However, most analysts recommend a “balanced” strategy using both disk and tape for backups. What you should really do is to formulate a disk and tape strategy based on stakeholder’s data management objectives and policies. A few considerations:
- Recovery time objectives. (RTO)/Recovery Point Objectives (RPO). Disk is typically faster for recovery.
- Archiving requirements. Tape is the most common archive medium.
- Service Level Agreements (SLAs). What is IT obligated to deliver to customers?
- Existing hardware investments, as well as budget.
The sensible strategy is to use disk where performance and flexibility are needed and use tape to reduce some costs. In most cases, IT will be moving to a disk-based infrastructure. However, the reality today is that tape is still widely used and should be accounted for in a virtual machine backup strategy.
Mistake #7: Backing Up Redundant Data
There is a lot of duplicate data on virtual machines. Consider the duplicate data in the OS, particularly if you use a standard image. It is simply not a wise strategy to backup all of that duplicate data. It congests the network, lengthens the backup window, and raises storage hardware costs. It is also completely avoidable. IT should consider the following strategies:
- Leverage VMware’s new vSphere block level differential/incremental backup and restore.
- Implement block-level data deduplication during backup of virtual machines to identify and exclude redundant data
The amount of duplicate data in virtual environments is significantly higher than physical environments - duplicate OS, cloned machines, test machines etc., all increase the amount of similar blocks in infrastructure. Deduplication can improve the backup speed. In the case of virtual machines there is a significant amount of duplicate data, allowing for major space and time savings.
In my next post, we will cover two common mistakes that unnecessarily add complexity to your life: treating backup as an island and failing to take full advantage of your SAN.