VM Backup taking much longer than expected

I have a setup where I backup PVE VMs to Backup Server. This setup has run for more than a year without any configuration change. Two months ago I observed a steep increase in the time it takes to backup one of the linux VMs. It went up from about 10min to more than one hour. And I fail to find any reasons for this increase.

Versions of PVE and Backup Server are current with respect to community version.

This is a copy of a part of the backup log that shows where the additional time is...

Read more