Google’s Cloud SQL service is now generally available, offering an alternative to Amazon’s Relational Database Service.

The Google service, which was initially in limited preview in October 2011 and has gradually added features and capacity, now  offers support for databases of up to 500GB, and automatically encrypted data. The encryption covers all database tables and temporary files, with encryption of backups “coming soon”, according to a post about the new service from Joe Faith on the Google Cloud Platform Blog in which he says that external connections can be encrypted using SSL.

Another security feature is the requirement that all hosts and Google App Engine applications connecting to your instance have to be explicitly authorized. You can use MySQL user grants to control access at the database, table, or even column level. Data is replicated multiple times in multiple locations.

The size of database has been increased from 100GB in the beta to 500GB per Cloud SQL instance for users with a silver support contract, with costs ranging from $0.025 per hour upwards. For this, your data is replicated multiple times in multiple zones and automatically backed up, and you’re charged for the storage that you actually use. The cost matches Amazon’s entry price in RDS for MySQL. The charges quoted for instance charges exclude storage and network charges.

The blog post says Cloud SQL has seen some “great developer traction”, with a range of businesses using it, including Costco, which has been using Google Compute Engine and Cloud SQL to run public e-commerce sites since October 2013.