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The virtual environment
Backup best practices are also affected by what's backed up. The widespread adoption of virtualized servers has significantly changed the server world. Virtualized environments, such as those supported by VMware, impact backup.
Backing up a virtualized server can be identical to backing up a physical server. It's possible to install backup client software and perform a traditional backup across the network. But what if 20 virtual servers reside on one physical server and they all try to back up at the same time? This can be a significant load-balancing concern, not to mention having to buy 20 client licenses for a single physical server.
It's also possible to back up a virtual machine as a single disk image. On a VMware ESX Server, each virtual machine exists as a file that can be backed up. It's therefore possible to back up all virtual servers as part of a physical server backup.
Individual virtual server backups allow for easy restore of files for normal operational restores, while image backups enable fast restores of an entire system for DR or migration purposes. It should be noted that in addition to backing up the individual virtual machines, the Linux-based VMware service console must also be backed up.
From a software perspective, the major backup apps provide support for a backup client running on a VMware virtual machine and on the service console, but it's critical to validate the appropriate version. If
Managing virtual machine backups on a multitude of physical machines can become complex. To address this, VMware Consolidated Backup was introduced with VMware Infrastructure 3. This product centralizes management of VMware backups, and supports quiescing of a virtual machine in addition to integrated snapshotting to a backup proxy server where both file-level and image backups can be performed. It provides much of its functionality through pre- and post-processing scripts that can be executed in conjunction with standard third-party backup client software.
Given the adoption rate of virtual servers, it's reasonable to expect further enhancements from existing apps and additional alternative approaches to protecting these environments. So, at this stage, best practices are still evolving.
Regardless of the technology selected, the fundamentals still apply when it comes to backup best practices: Policy, process and metrics are the keys to ensuring successful and recoverable backups.
This was first published in September 2006