Scale-Out Backup Repository Offload task fails with "There is not enough space on the disk"

• The gateway server for an Object Storage Repository is assigned on the Account tab of the Object Storage Repository creation wizard^[1]. If a gateway server is not explicitly assigned, Veeam Backup & Replication will assign the role of gateway server to one of the Performance Tier repository servers.
• The default cache folder used on the gateway server for Offload tasks:
  • Windows Gateway: %temp%\VeeamBackupTemp
    As the service on the gateway runs under the System account, %temp% is C:\Windows\Temp\
  • Linux Gateway: /root/tmp/VeeamBackupTemp
  • Hardened Linux Gateway:  /home/%user_name%/tmp/
    Where %user_name% is the account provided as part of the one-time credentials.
• The amount of space required is based on the amount of data being offloaded during a given offload session's sub-task—approximately 2GB per 1TB of data actively being offloaded at a given time. If multiple offload sub-tasks occur during a session, only the active sub-tasks will require cache space.

Option 1: Increase free space on Gateway Server

• If a specific server has been selected to be the gateway server^[1] for the Object Storage Repository, review the free space of that machine and ensure that the default location has sufficient free space. 
• If no specific server has been selected to be the gateway server, review each of the Windows\Linux repository servers acting as Performance Tier extents of the Scale-Out Repository and ensure sufficient free space is available. 
  

Option 2: Use a different Gateway Server

Edit the Object Storage Repository assigned as the Capacity Tier for the Scale-Out Backup Repository and assign a gateway server^[1] with sufficient free space.