Google Storage for Developers (GSD) is a new RESTful service providing data storage which is replicated across several data centers located in US. GSD is called “for Developers” because data is transferred and accessed though an API based on regular HTTP commands like GET, POST, PUT, HEAD, and DELETE.
The service is currently in preview phase being offered to a limited number of current Google service developers (sign-up link), each account receiving 100GB of storage and 300GB of bandwidth. Data is stored as objects organized in a flat hierarchy inside buckets. Buckets are also organized in a flat hierarchy inside an account, all buckets sharing one common namespace across GSD. Each account is allowed to create up to 1,000 buckets, and each object can be as large as 100GB, but those numbers are supposed to increase when the preview phase is over.
GSD provides read-after-write consistency which basically means that an object can be accessed - listed, downloaded, or deleted – right after uploading. Also, a deleted object is no longer accessible right after the erasing command. Also, listing commands are eventually consistent from everywhere on the Internet.
GSD supports access control lists (ACL) based sharing. There are various permissions – read, write, full control - assigned to users, and access granularity established at bucket or object level.
Storage management can be performed through the GS Manager, a browser based application offering support for the most actions: creating/deleting buckets, uploading/downloading/deleting objects, managing ACL lists. The application requests one of the following browser versions to run: Google Chrome 5.0, FireFox 3.6, Safari 4.0 or higher. Another tool is GSUtil, an open source command line tool used to perform the same tasks as GS Manager.
GSD is currently not integrated with Google Docs and Google Apps accounts do not work, only regular Google accounts, but that is going to change in the future.
Pricing is set at $0.17/GB/month, higher than that of the similar Amazon S3 pricing which is set at $0.15/GB/month for 11 nines durability and $0.1/GB/month with 99.99 durability. Uploading and accessing are the same at $0.1/GB and $0.01/1000 HTTP requests. Amazon has progressive discounts for storage in excess of 50 TB, 400TB, 500TB and so on. There is no SLA for GDS yet, but Google promises to provide one when the service will be open to all those interested.