I was searching a lot about this issue and can't find any relative information.

I have a MSSQL Server instances running on Google Cloud for MSSQL, and I'm trying to import a database bak file that was generated with other instances of same product (Google Cloud for MSSQL). The size of the bak file is 1.4GB, but when I import it, the space that it uses is around 250GB. I tried to configure a fixed disk space of 100GB (No autoscaling) and when I try to import It shows up an error of insufficient disk space.

I don't understand why is taking so much disk space if the bak file only has 1.4Gb, and how can I reduce such occupied space.

This database originaly was around 170GB big, but we do some cleaning and we were able to reduce it to 1.4GB. This is why we created a new MSSQL instance to import the bak file and reduce the used disk space.

The MSSQL version we are using is 2019 Standard on both, the source and the destination.

Please let me know if I need to post some other information.

Thank you all.

  • 1
    What command did you use to make the restore? Probably easier to just shrink the database files before you create the backup Commented May 21, 2023 at 12:40

1 Answer 1


The size of the bak file is 1.4GB, but when I import it, the space that it uses is around 250GB.

Database backups only contain the extents that have data in your database files, not the unused space. But the first step in a RESTORE is to recreate all the database files with the same sizes they had when you took the backup.

If you really need to you can shrink the source database before the restore or the target database after.

  • Thank you David, that is exactly what I need, after do the shrink the database reduces its space and I can import it without problems. Thanks a lot.
    – Les
    Commented May 22, 2023 at 15:55

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