I’m new to Commvault and started running some Virtual Server full backups and they seem to be slower than I expected. These are on thin provisioned disks if that helps. Any ideas?
Solved
Why is the backup throughput very low during the full backup?
- Vaulter
- 5 replies
Best answer by Stogs
If you are performing a full backup of virtual machines which have thin provisioned disks on NFS datastore, the backup throughput may become very low. VMware does not support the retrieving allocated blocks on NFS volume. Therefore, if a NFS datastore has a thin provisioned disk, the software reads the complete disk during the full backup. This reduces the backup throughput during the full backup. In case of incremental backups, software uses Change Block Tracking (CBT) and thus reads and backs up only the changed data.
For more information, refer to “Changed Block tracking on Virtual disks" section in the following document:
https://docs.vmware.com/en/VMware-vSphere/index.html
If the Thin provisioned disk is on VMFS volume, the software reads and backs up only the allocated part of the disk.
- Vaulter
- 16 replies
- Answer
If you are performing a full backup of virtual machines which have thin provisioned disks on NFS datastore, the backup throughput may become very low. VMware does not support the retrieving allocated blocks on NFS volume. Therefore, if a NFS datastore has a thin provisioned disk, the software reads the complete disk during the full backup. This reduces the backup throughput during the full backup. In case of incremental backups, software uses Change Block Tracking (CBT) and thus reads and backs up only the changed data.
For more information, refer to “Changed Block tracking on Virtual disks" section in the following document:
https://docs.vmware.com/en/VMware-vSphere/index.html
If the Thin provisioned disk is on VMFS volume, the software reads and backs up only the allocated part of the disk.
Reply
Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.