The information dialog guiding you through the update and migration process provides estimated size requirements and informs you if the available space in the GeneSpring installation directory is not sufficient. PostgreSQL migration involves copying the entire MySQL folder. The MySQL folder will remain untouched after migration. This means, if the MySQL folder occupies x GB space, you will need at least twice that amount (2x) plus some extra space, which varies, but is typically around 10% of the size of the original MySQL folder (10% of x). Therefore the total space requirement is approximately 2.1x.