Accelerator notes and requirements for virtual machines
Note the following about Accelerator for virtual machines:
Accelerator for Hyper-V is available for virtual machines on Hyper-V Server 2016 and later. In the web UI open the Hyper-V policy. Click the policy's Hyper-V tab and select . Then select and .
Accelerator for virtual machines uses Hyper-V resilient change tracking (RCT) to identify the changes that were made within a virtual machine.
After the first Accelerator backup: If you create a checkpoint on the VM (or delete a checkpoint), the next backup from that policy is a full backup. That is, the backup processing for the second backup is not limited to changed blocks: Under Accelerator Optimization in the NetBackup Activity Monitor, the optimization rate is 0%.
If you create another checkpoint and run a third Accelerator backup: The optimization rate may increase, depending on the amount of data that is captured in the checkpoint (the size of the checkpoint file). The smaller the checkpoint file, the higher the rate of optimization in the third backup.
Similarly, if a checkpoint is deleted after the second backup, the optimization rate in the next backup depends on the size of the virtual disk that was affected by the checkpoint deletion.
Supports the disk storage units that have the following storage destinations:
Cloud storage. Storage that a supported cloud storage vendor provides.
NetBackup Media Server Deduplication Pool. In addition to NetBackup media servers, NetBackup 5200 series appliances support Media Server Deduplication Pool storage.
Qualified third-party OpenStorage devices.
To verify that your storage unit supports Accelerator, refer to the NetBackup hardware compatibility list for the currently supported OST vendors:
It is recommended that you do not enable Expire after copy retention for any storage units that are used with storage lifecycle policies (SLP) in combination with Accelerator. The Expire after copy retention can cause images to expire while the backup runs. To synthesize a new full backup, the SLP backup needs the previous backup image. If the previous image expires during the backup, the backup fails.
Update the NetBackup device mapping files if needed.
The NetBackup device mapping files contain all storage device types that NetBackup can use. To add support for the new devices or upgraded devices that support Accelerator, download the current device mapping files from the Cohesity Technical Support website.
See the NetBackup Administrator's Guide Volume I for information on the device mapping files and how to download them.
Storage unit groups are supported only if the storage unit selection in the group is Failover.
Supports the full backups and incremental backups. Every Accelerator backup (from a full schedule or incremental schedule) results in a complete image of the virtual machine.
You can use incremental backups (cumulative or differential) as follows: To reduce the file-mapping overhead and to reduce the number of files that are recorded in the NetBackup catalog. Cumulative backups may involve more file-mapping because they do not use the random indexing method to determine which files have changed. In some cases, differential backups may be faster than cumulative backups.
If a backup of the virtual machine does not exist, NetBackup performs a full backup. This initial backup occurs at the speed of a normal (non-accelerated) full backup. Subsequent Accelerator backups of the virtual machine use resilient change tracking (RCT) to accelerate the backup.
If the storage unit that is associated with the policy cannot be validated when you create the policy, note: The storage unit is validated later when the backup job begins. If Accelerator does not support the storage unit, the backup fails. In the bpbrm log, a message appears that is similar to one of the following:
Storage server %s, type %s, doesn't support image include.
Storage server type %s, doesn't support accelerator backup.
Accelerator requires the storage to have the
OptimizedImageattribute enabled.