Since one policy can be used to protect multiple workloads at the same time, it is recommended that you limit the number of processed workloads to simplify the backup schedule and to optimize the backup performance.
This section provides best practices for the maximum number of workloads per policy. This number does not depend on the Azure VM size of the backup appliance.
Maximum Workloads per Policy
Azure SQL Database
With 50 workloads per policy, the expected writing speed to the target backup repository is approximately 7.3 GBps (engaging 50 worker instances of the F8s_v2 Azure VM size), which falls under the ingress limit for Azure storage accounts (7.5 GBps or approximately 60 Gbps). It is possible to protect more then 50 workloads per policy; however, you must configure the load options for the target backup repository as described in section Adding Backup Repositories.
The number of worker instances simultaneously launched to process workloads added to a policy is defined by the speed of data upload to the repository specified for the policy. To maximize policy processing throughput, take into account that every backup and archive session started during policy execution requires a separate worker instance to be launched. For more information, see Worker Instances.
For example, one backup policy can only write to one storage account. When using a F2s_v2 worker size with 80 MBps throughput to a storage account that can handle 25 Gbps, you can have a maximum of 3 GBps of throughput to the storage account, so a maximum of 38 worker instances. This means that for a policy that protects approximately 50 workloads, the recommended maximum number of worker instances processing simultaneously is 38.
Workloads in Policy
Recommended Maximum Number of Worker Instances
Worker Instance Size
Worker Instance Throughput
Storage Account Throughput
(change to fit maximum storage account throughput)
(change to fit whatever size you choose)
38 * 80 MBps or ~3 GBps
25 Gbps or ~3 GBps
(check your specific storage account type and region)