AWS vs GCP storage

I have a few databases with several TB-sized tables. We recently moved one of those databases from AWS EC2 to GCP. Today I ran VACUUM FREEZE on those tables and every time I saw our application freezing up (and throwing tons of errors) for a few minutes right after the message about the end of vacuum (duration: 30182257.392 ms  statement: vacuum freeze verbose ...). We never saw anything like that on AWS.

The database is 9.6. At the moment I have no details about the storage configuration on GCP. The machine was set up by another department.

Any suggestions on why that is happening and how to prevent it would be appreciated.

Thanks,

Torsten