Recommendations

For SQL Server sizing recommendations, see Zerto Scale and Benchmarking Guidelines.
Zerto uses username/password authentication. This is because using Windows credentials requires a manual change of the Zerto Virtual Manager Service account (step 9 > Authentication parameter).
Although Zerto supports SQL Server Enterprise/SQL Express Server/SQL Server Standard editions, when migrating to an external SQL Server service, Zerto recommends using Standard or Enterprise edition.

See also:

Considerations

Verify SQL Permissions and Roles