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VB365 Backup Proxy Server

Depending on the service offering, there are a few things that should be considered:

RAM allocation and number of Repository databases per Proxy

Each Proxy/Repo needs to have enough resources available for OS operations and VB365 server operations. Therefore we need to reserve a minimum of 15% host memory not allocated to other processes.

A simple example shows that the JetDB engine itself consumes 50% of the host’s memory. Running 250 databases on it adds another 0.1% on top per instance resulting in 25% memory usage. This leaves us with 25% of the available memory for VB365 operations and the OS.

Type Value
Default JET database instance memory consumption on Veeam Backup for Microsoft 365 repository 0.1% of host memory
Default JET database engine memory cache 50% of host memory
Recommended maximum number of JET databases per backup proxy 250
Max number of JET databases per backup proxy 750

Source: VB365 BP Guide

User Guide


  Proxy/Repo Server  
OS Windows Server 2019  
CPU 8 Cores  
RAM 32 GB  
Disk 1 50 GB OS + 300 MB for production installation + additional free space for the configuration database and logs.
Disk N Backups/Cache Size depends on the backup repository type that will be used.

Proxy servers scale horizontally (up to 50 per VB365 Server). Each proxy adds capacity to process up to 20.000 objects or -+ 5000 users. (More details.)

Backup/Cache disk sizing:

  • Using JetDB-backed repositories
    • This repo type consists out of multiple folders named after the number of years of retention. For each year’s folder there is a repository file (.adb) plus a transaction and check log (.jrs and .chk). The maximum size per .adb file is 64 TB. To counter that limit an automatic rule triggers the generation of a new repo file in the same storage location when reaching 59 TB. For example, three-year retention creates three folders with one or multiple .adb files in it which each can grow up to ~60TB.
    • A proper sizing must be done as disks/volumes need to be large enough to hold the entire backup data’s retention.
  • Using Object storage repositories
    • JetDBs are only being used as cache to hold meta data. Therefore the available space should be only around 1-2% of the source data.
    • More (cache) databases fit on the same proxy and much less space is required as all backup data is stored in object storage.

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