Proxy & Repository Server

Repositories are tightly coupled with proxy servers. While a single proxy server can host multiple repositories, each repository is uniquely coupled with a single proxy server.

Repositories can reside on Direct Attached Storage (DAS), Storage Area Network (SAN) volumes or on a SMB3 Network Attached Storage (NAS) share and contain Microsoft Jet databases (.adb).

From v4 of the product object storage repositories are also supported. For these only a small cache is used locally (usually ~1% of the whole repository size) and all other content is directly stored in the object storage bucket/container. For one repository you can either use local block storage or object storage. There is no tiering functionality in between these storage types as in VBR.

Best Practice Notes

Disk Repository

  • Use high throughput low latency storage. Thus DAS or SAN are preferred storage volumes for repository. Go with the default controller and stripe size settings.
  • Repository File System should be chosen as NTFS with default settings (4k allocation units).
  • Do not enable storage encryption, dedup or compression on the repository volume for better performance
  • Separate repositories by data type (Exchange, OneDrive, SharePoint) to allow higher flexibility based on the different data-change characteristics
  • Avoid very large repositories because handling them gets harder. Distribute the backup data over several repositories, e.g. split by business units
  • Keep 10% free working space per repository to avoid lock downs

Object Storage Repository

  • General security best practices apply - create an own storage user with own credentials for the bucket/container, apply restrictive ACL
  • Do not setup tiering policies on the object storage side. This is not supported and will break things.
  • Do not manually delete anything from the object storage bucket/container, unless you don’t want to use the repository anymore (then you can delete everything)
  • Provide disk space for ~1% of your source data size as local cache. In case of restores this local cached metadata reduces the need of 90% of the required API calls to the object storage (which might incurr cost on public cloud)


  • Throttle the used bandwidth per proxy on a shared network connection to not block other applications

More in-depth information on this item

External Resources