Challenge
Backup Job for VMs from ESXi hosts with "Content Based Read Cache" (CBRC) enabled fail and and the following error is shown:
Error Hot-add of digest enabled disk not supported scsi0:1.
Error Failed to attach disk 2000 to source Linux backup proxy <IP address> (<GUID>) (System.Exception)
Cause
This issue occurs if a Linux-based VMware Backup Proxy is used by a backup job because when Veeam tries to hot-add a virtual disk to a VM which is deployed on the ESXi host with the CBRC option enabled.
Due to a VMware limitation, when CBRC is enabled, it is impossible to attach disks to VMs while powered-on.
According to VMware documentation, the CBRC feature was introduced in vSphere 5.1, which may affect all systems with this version and above.
Solution
To resolve this issue, upgrade to Veeam Backup & Replication 11 or newer. The most recent version of Veeam Backup & Replication can be found here. Starting with Veeam Backup & Replication 11, new transport mode options are available to Linux-based VMware Backup Proxies, meaning that the proxy will be able to failover to use nework transport mode and the job will not fail.
Workaround
If it is not possible to upgrade Veeam Backup & Replication to version 11 or newer, the following workarounds may be used with Veeam Backup & Replication 10:
Power-off the VM that you want to back up during the backup operation.
Note: You could write a pre-job script using VMware PowerCLI to turn shut-down the VM.
or
Create a new backup job for the affected VMs and assign a Windows-based VMware Backup Proxy with Failover to network mode enabled to the job.
or
Turn off the CBRC option the in ESXi host settings. To learn how to turn off the CBRC option, see the VMware Horizon 7 Documentation, section Configure View Storage Accelerator for vCenter Server.
More Information
VMware KB: Hot-adding a hard disk to a powered-on virtual machine fails with the error: Hot-add of digest enabled disk not supported (2072804)
