ETA for image backups

How is the ETA time remaining for image backups calculated?

Image backups are able to complete successfully but the ETA timing are showing 12 hours when the actual job only took 15 minutes to complete.

Anyone experiences the same?

Just wondering if anyone else have experienced the same?

Calculating an ETA for anything on a computer is nearly impossible.

For most thingsā€¦it is impossible. Transfer a large file across the network in Windows and expand the details on the file transfer and you will see the time jump around nearly constantly from minutes to hours, to possibly days. And that is the best that a company with a multi-million dollar budget can do it.

Take any estimated time to completion that a program or operating system gives you with a grain of salt. There are too many variables and it would be foolish to try to compensate for all of them as you would be potentially tying up resources that would be better spent completing the process you are trying to estimate an ETA for.

Yes. I fully agree with you on this. Just wondering because the estimations for file backups are not that far out though.

Only for image backups, the eta sometimes shows 2 days while job only took 20 minutes to complete.