You are here: VMware Protection > Best practices for protecting VMware virtual machines

Best practices for protecting VMware virtual machines

Unitrends scalable agent/agentless architecture offers several options for protecting your VMware virtual machines. Typically, the Unitrends Virtualization Protector is used to backup and restore VMs, but there are cases where installing the agent is recommended. Factors in your environment, such as the type of data you need to protect, recovery time objectives, storage capacity, retention requirements, and backup window should all be considered to determine the best strategy.

You can use either of the strategies described here, in any combination, to tailor protection to best suit your needs. When you register the vCenter or ESX server, all VMs are discovered and available for backup using the Virtualization Protector (vProtect). To back up using the agent, register the VM to the backup system as you would a physical client (see About adding clients for details) and follow the instructions in the applicable chapters to run backups. If you will be protecting some VMs with the agent and others using vProtect, it is best to protect each VM using one method only. This way you won’t needlessly back up the same data twice.

Example recommendations are given here:

• To protect SQL or Exchange application data, either method provides application-aware protection leveraging the applicable Microsoft VSS writers. vProtect is the recommended method unless you need to have more granular control of which data is included in the backup or have SQL databases that do not use the simple recovery model.
• To protect a VM with both vProtect host-level and file-level (agent-based) backups, be sure to adhere to the following:
– Ensure that the VM's host-level and file-level jobs do not overlap. Running both simultaneously may lead to undesirable results.
– If protecting hosted SQL or Exchange databases with agent-based application backups, do not use application-aware protection for vProtect host-level backups.
• If recovery time objectives are very important, instant recovery is the fastest way to spin up a failed VM. Run vProtect backups to use this feature.
• vProtect backups can exclude data at the virtual hard drive level only. If you have a requirement to exclude data at the directory or file level, or if you don’t have space in your VMFS datastores for snapshots of your VMs, consider using agent-based backups.
• For Recovery Series systems protecting ESX hosts whose datastores are located on an external SAN, consider implementing SAN-direct VMware backups. These backups run more quickly since network bandwidth is not a hit to performance. See VMware SAN-direct backups for details.
• For Unitrends Backup on VMware systems protecting ESX hosts whose datastores are located on an external SAN, consider implementing HotAdd VMware backups. These backups run more quickly since network bandwidth is not a hit to performance. See VMware HotAdd backups for details. (HotAdd backups are not supported for Unitrends Backup on Hyper-V systems.)
• For virtualized Active Directory servers, there are additional considerations when determining whether to use vProtect or agent-based backups. See Protecting virtualized Active Directory servers for details.
• For virtual machines in Distributed File System environments, there are additional considerations when determining whether to use vProtect or agent-based backups. See Protecting virtual machines in Distributed File System environments for details.
• If you are registering an ESX or vCenter server to multiple Unitrends appliances, you should back up each VM on only one appliance. Backing up the same VM on multiple appliances causes problems with the Change Block Tracking information used for incremental and differential backups. To avoid backing up a VM on more than one appliance, you can use the navigation grouping feature to create groups of VMs associated with particular appliances. For details, see Grouping VMware virtual machines.

See the table below for a comparison of vProtect versus agent-based backups.

VMware protection strategy

Considerations

Virtualization Protector backup
• Quickest setup. You do not need to register VMs individually.
• Features auto-detection of new VMs.
• Excludes at the disk level. No exclusions of individual directories or files. Leverages VMware’s VADP framework to perform application and operating system consistent backup and restore.
• For SQL simple recovery mode databases, provide guest-level credentials for application-aware protection. The application database is quiesced to ensure a consistent state in your VMware backup.
• For other database recovery models, use agent backup or use application-aware backup along with separate transaction log backups to truncate SQL logs. (You can schedule transaction log backups using SQL Maintenance Plan. Be sure that you do not use a SQL Maintenance Plan with agent-based backups.)
• Do not use for single-node or multi-node SharePoint farms. Use agent backup instead.
• For Exchange, provide guest-level credentials to ensure application consistency and to perform application-level post backup processing, such as log truncation.
• For Unitrends Recovery Series appliances, supports SAN-direct backup to reduce backup window and off-load network bandwidth utilization.
• For Unitrends Backup on VMware systems, supports HotAdd backup to reduce backup window and off-load network bandwidth utilization. HotAdd backup is not supported on Unitrends Backup on Hyper-V systems.
• Supports VMware instant recovery to quickly spin up a failed VM.
• Supports backup of VMware templates.

Agent backup
• Backup system treats the VM like a physical client.
• All backup options are supported, including selection lists, options to exclude at the volume, directory, or file level, and run pre- and post- backup commands. Recommended for VMs where more granular exclusion of data is required.
• For SQL, Exchange, Oracle, and SharePoint backups, provides application and operating system consistent backup and restore.
• Supports all SQL database recovery models. Must use agent for all recovery models other than simple.
• Supports backup of single- and multi-node SharePoint farms.
• Does not support SAN-direct or HotAdd backup.
• Supports Windows instant recovery (WIR) to quickly spin up a virtual replica of a failed Windows client.
• Does not support backup of VMware templates.