File to tape job significantly slows down due to garbage collection operations

Challenge

A file to tape job significantly slows down after some time of processing. The source disks and the Veeam database are under a low load, CPU is not overloaded either. Available RAM on the Veeam server is around 10% or lower.

Cause

When available RAM on the Veeam server reaches a certain threshold (by default, 10% of total RAM installed), .NET Framework activates frequent garbage collection operations. This leads to the freezing of Veeam Management processes.

Solution

Do the following to enable the Server Mode for garbage collection:

1. Make sure no Veeam job is running.
2. Disable Veeam services on the Veeam Backup & Replication machine.
3. Navigate to the product installation folder. The default installation folder is C:\Program Files\Veeam\Backup and Replication\.
4. Open the Backup subfolder.
5. Back up the Veeam.Backup.Manager.exe.config file to avoid file corruption.
6. Open the Veeam.Backup.Manager.exe.config file for editing.
7. Find the <runtime> tag, create a new blank line after it and add the following element to the new empty line:

<gcServer enabled="true"/>

For an XML example, see the following Microsoft article.
https://docs.microsoft.com/en-us/dotnet/framework/configure-apps/file-schema/runtime/gcserver-element

Please note that RAM consumption can increase significantly if multiple jobs run concurrently. Enabling garbage collection at the server requires additional 1-2 GB RAM for every Veeam job.