Add auto vacuum interval option #3840 allows “every now and then” tuning. Here’s 2.0.5.1 Beta help:
C:\ProgramData\Duplicati\duplicati-2.0.5.1_beta_2020-01-18>Duplicati.CommandLine.exe help auto-vacuum-interval
--auto-vacuum-interval (Timespan): Minimum time between auto vacuums
The minimum amount of time that must elapse after the last vacuum before
another will be automatically triggered at the end of a backup job.
Automatic vacuum can be a long-running process and may not be desirable
to run after every single backup.
* default value: 0m
however it looks like you still need to turn it on yourself, and preferably pick an interval above 0m.
–auto-vacuum-interval = 0m is the default value? discusses the difficulty of picking the right value.
--auto-vacuum (Boolean): Allow automatic rebuilding of local database to
save space.
Some operations that manipulate the local database leave unused entries
behind. These entries are not deleted from a hard drive until a VACUUM
operation is run. This operation saves disk space in the long run but
needs to temporarily create a copy of all valid entries in the database.
Setting this to true will allow Duplicati to perform VACUUM operations at
its discretion.
* default value: false