How to do it...

1. Type the following command:

      aws rds restore-db-instance-from-db-snapshot \
        --db-snapshot-identifier <name-of-snapshot-to-restore > \
        --db-instance-identifier <name-for-new-db> \
        --db-subnet-group-name <your-db-subnet-group> \
        --multi-az

2. You may have noticed that this command creates a new database in the default security group. This happens because the restore-db-instance-from-db-snapshot doesn't accept a security group ID as a parameter. You'll have to run a second command to assign a nondefault security group to the new database:

      aws rds modify-db-instance \
        --db-instance-identifier <name-of-newly-restored-db> \
        --vpc-security-group-ids <id-of-security-group>

The modify-db-instance command will return an error unless the state of the target database is available.
Also, security group names aren't valid with this command; you'll need to use a security group ID instead, for example, sg-7603d50a.