ABAP report /VIRSA/ZVFATBAK run very long on backend

Hello experts,

For ABAP report /VIRSA/ZVFATBAK which runs in the backend system, normally how long would it take to finish? Because now the duration for the report is already 2k++ seconds and its still running in our test system, while the report scheduled in our development system only uses 1 or 2 secs to finish.

Any idea why is it taking that long in a test system?

Appreciate the replies, thank you in advance.