Summary

In CCMA, the estimated migration time is largely different with the actual migration period.

This is because, the estimation calculates from space stats even in attachment only migration, and it is done in simple math from hardcoded value, regardless hardware, concurrency, database performance etc

Expectation

The estimated time should be aligned or closed enough to the actual migration running time.

Otherwise, this causes confusions to users.

If CMA could have better calculation with variables obtained on the DC instances, it would be much more accurate.