problem

Similar test case to #11257

versions

ACS 4.20 upgraded to 4.21

The steps to reproduce the bug

1. Create a volume of size 5gb in 4.20
2. Create an instance with root disk size 8GB in 4.20
3. Attach the data volume to the Instance
4. Take a NAS backup
5. Upgrade to 4.21
6. Create new instance from the backup
7. It fails with the error
   Instance volume size 5368709120[GiB] for| volume (0b99777b-8c49-458c-8ffa-f999b1698908) is less than the backed-up volume size 8589934592[GiB] for backed-up volume (74e619c9-7643-4031-9273-e9ec78d432e3).
   ...

What to do about it?

Create new Instance from Backup should succeed.