Worker Instances

To optimize the performance of backup and restore operations, you can configure worker profiles as described in section Managing Worker Instances.

When configuring worker profiles, you can use simple or advanced configuration. It is recommended that you use advanced configuration to ensure the profile of each launched worker instance is selected based on the performed operation, and on the total size of the processed workload.

If you want initial full backups to be processed quickly, it is recommended to use a larger worker profile, and then change it to a smaller profile for incremental backup. You can change worker profile settings on a regional basis, so make sure that the Azure VM sizes of worker instance size is appropriate to process the largest workload within the required time.

Each worker instance is deployed as an Ubuntu image, and the binaries are downloaded from the provisioning Azure storage account. Azure VM sizes of worker instances depend on the total size of virtual disks attached to the processed Azure VM, on the total size of the processed Azure SQL database, or on the total size of the processed Cosmos DB for PostgreSQL cluster.


Azure VM Size


Backup Speed



Backing up workloads with disks smaller than 100 GB (default)

70-85 MBps



Backing up workloads with disks between 100 GB and 1 TB (default) 

90-100 MBps



Backing up workloads with disks over 1 TB, also recommended for initial full backup (default)

125-140 MBps



Data tiering (default) 

85-110 MBps


For more information on Azure VM pricing, see Microsoft Docs.

Recommended Maximums

You can modify the default number of worker instances to reduce the amount of processing time, and choose profiles that will be used to launch worker instances in the selected regions to boost operational performance. For more information, see Adding Worker Profiles.


If you are planning to perform operations that require more than 50 worker instances at a time, or if you want to use custom worker profiles for retention operations or for Cosmos DB backup and restore, open a support case.



Recommended Maximum Number of Worker Instances

Default appliance size


Medium appliance size 


Large appliance size


Maximum per region per appliance


Azure ARM API reads (per tenant/user/hour)*


Azure ARM API writes (per tenant/user/hour)*



*For more information on the Azure Management API request limits and throttling, see Microsoft Docs.

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