So far, I’ve looked at options for hosting .NET and Node.js applications in the cloud. But what about the services that web applications rely on? It’s unlikely that your cloud application will use many on-premises services, so you’ll need things like databases nearby. There are a LOT of relational and NoSQL cloud databases out there. While it’s a perfectly reasonable choice to install and operate a database yourself on someone’s cloud VMs, this assessment looks at “managed” cloud databases. A managed cloud database typically takes care of underlying VM management as well as database tasks like backups.
I’ve picked out 8 diverse choices (although MANY other interesting services exist), and evaluated them using the following criteria:
Type of offering (RDBMS, NoSQL)
Technology and versions supported
Scalability story
High availability options
Imposed constraints
Pricing plans
Administrative access
Support material offered
There are other important factors to consider before actually selecting one of the services below. Make sure to look deeply at the feature set (and lack thereof), SLAs, and data privacy policies.
Once again, I’m putting these in alphabetical order, which means that Amazon Web Services shows up first, and Windows Azure last. Just like that crafty Jeff Bezos wants.
Amazon Web Services
AWS has a variety of database services that offer excellent scale and innovative features.
Type of Offering
Tech and Versions
Scalability
High Availability
Relational, NoSQL, and warehouse
RDS uses MySQL (5.6.13 and lower), SQL Server (2012, 2008 R2), and Oracle (11.2)DynamoDB is proprietary NoSQL database.
Redshift is a proprietary data warehouse platform.
Manually scale RDS instances up and down with minimal downtime.DynamoDB scaling is done by increasing or decreasing the “provisioned throughput” with impacting availability.
Redshift scaling occurs by adding or removing nodes in the cluster.
RDS instances scale up, but do support high availability through “Multi-AZ Deployments” for MySQL or Oracle.DynamoDB is built for high availability by default. Its data is spread across AZs in a region and can withstand server or AZ failure.
Redshift replicates data across nodes in a (single AZ) cluster and constantly backs up to S3.
Constraints
Pricing
Admin Access
Support
For RDS, MySQL or Oracle databases can be up to 3TB in size with 30k IOPS. SQL Server databases can be 1TB in size with up to 10k IOPS.DynamoDB supports up to 10k read/write capacity units (unless you receive special permission). Items can only be 64kb in size, but there is no size limit on an entire table.
Redshift supports 16 XL nodes (2TB apiece) or 16 8XL nodes (16 TB apiece) per cluster.
RDS pricing includes an hourly charge for the instance, primary storage, Multi-AZ storage, backup storage, and data transfer out.The pricing in DynamoDB is pretty simple. Pay for provisioned throughput units, storage, and data transfer out.
For Redshift, you pay for capacity per hour, backup storage, and in some cases, data transfer.
RDS users can create firewall policies that let them use standard client tools for connecting to DB instances.Few admin tasks exist for DynamoDB, but can use AWS Console and API.
Access Redshift via API, and database/BI tools.
For RDS, lots of documentation, some tutorials, support forums, and paid support.DynamoDB has documentation, forums, and paid support.
Redshift is new, but you’ll find good documentation, forums, and paid support.
Cloudant
Cool provider of a distributed, cloud-scale JSON document database. Good when you need a high-performing, CouchDB-friendly environment.
Type of Offering
Tech and Versions
Scalability
High Availability
NoSQL (document DB)
Cloudant developed BigCouch which is a fork of CouchDB.
Scaled horizontally by Cloudant. Run as shared (AWS, Azure, Joyent, Rackspace, SoftLayer) or dedicated (AWS, Rackspace, SoftLayer).
Supports cross-data center, multiple writable masters.
Constraints
Pricing
Admin Access
Support
No apparent limits on DB size.
For shared hosting, pay for data volume and HTTP requests.
Compatible with CouchDB API so admins can use other CouchDB-friendly tools. Most of the admin activities are performed by Cloudant.
Some documentation, and 24×7 support.
Engine Yard
Long-time PaaS provider offers a handful of different managed databases. One of the rare Riak hosters online so far, Engine Yard is good bet for DB hosting if your app is running in their cloud.
Type of Offering
Tech and Versions
Scalability
High Availability
Relational and NoSQL.
Relational options include PostgreSQL (9.2.x) and MySQL (5.0.x).For NoSQL, EngineYard offers hosted Riak and supports all possible Riak storage backends.
EngineYard databases run in AWS.
Can scale PostgreSQL and MySQL servers up to larger server sizes.Riak is setup in a cluster, and it appears that clusters can be resized.
PostgreSQL and MySQL can be set up with read replicas, and replication, but those appear to be only HA options.Riak cluster is set up in an AWS region, and balanced between AZs.
Constraints
Pricing
Admin Access
Support
PostgreSQL and MySQL databases can be up to 1TB in size (EBS backed).Riak service appears to support up to 1TB per node.
Hourly pricing (based on server size), with no extra charge for the database software. Also pay for backups and bandwidth.
Access databases from the outside using SSH tunnels and then your preferred management tool.
Offer knowledge base, ticketing system, and paid support plans.
Google
Google offers a couple different databases for cloud developers. The options differ in maturity, but both offer viable repositories.
Type of Offering
Tech and Versions
Scalability
High Availability
Relational and NoSQL.
Google Cloud SQL in based on MySQL (5.5).The Google Cloud Datastore is a preview service and came from the Google App Engine High Replication Datastore (BigTable).
For Cloud SQL, users can switch between instance sizes to adjust capacity.Cloud Datastore writes scales automatically.
Cloud SQL supports either sync or async replication to multiple geographic locations.Cloud Datastore is replicated (in real time) across data centers.
Constraints
Pricing
Admin Access
Support
For Google Cloud SQL, Maximum request/response size is 16MB. Databases can be up to 100GB in size.The Cloud Datastore has no maximum amount of stored data, up to 200 indexes, and no limit on reads/writes.
Google Cloud SQL can be paid for in package (per day) or per-use (hourly) billing plans. Per-use plans include additional per-hour charge for storage. Both plans requirement payment for outbound traffic.For the Cloud Datastore, you pay an hourly per-GB charge, plus a cost per 100k API operations.
Use client tools that support a JDBC connection and Google Cloud SQL driver. Also supports a command line tool.Developers use a tool from Google (gcd) to manage the Cloud Datastore.
For Google Cloud SQL, you’ll find documentation, discussion forums, and paid support.Support for the Cloud Datastore can be found in communities, documentation, and a free/paid ticketing system.
NuoDB
Offers a “newSQL” product which is an object-oriented, peer-to-peer, transactional database. Powerful choice for on-premises or cloud data storage.
Type of Offering
Tech and Versions
Scalability
High Availability
Relational.
Proprietary, patented technology base.
Supports manual scale out of more hosts and can also apparently add capacity to existing hosts.
Journaling ensures that writes are committed to disk, and they offer multiple ways to configure the hosts in a highly available (geo-distributed, multi-master) way.
Constraints
Pricing
Admin Access
Support
Amazon-hosted version has 1TB of storage, although seemingly you could add more.They also list a handful of SQL-related limits for the platform.
NuoDB has three editions. The developer edition is free, the Pro version is “pay as you scale”, and the cloud version is based on usage in AWS. See here for a comparison of each.
Offer a handful of CLI tools, visual consoles, and integration with 3rd party management tools.
NuoDB offers documentation, GitHub samples, and support forums.
Rackspace
This leading cloud provider sells their own managed cloud database, and recently acquired another. Good choice for apps running in the Rackspace cloud, or if you need a well-engineering MongoDB environment.
Type of Offering
Tech and Versions
Scalability
High Availability
Relational and NoSQL (document)
Cloud Databases run MySQL (5.1).ObjectRocket is based on MongoDB.
Cloud Databases can be scaled up, but not out.ObjectRocket scales out to more sharded instances. Can happen automatically or manually.
The Cloud Database relies on SAN-level replication of data, and not MySQL replication (unsupported).The ObjectRocket “pod” architecture makes it possible to replicate data easily. load balancers are in place, geo-redundancy is available, and backups are built in.
Constraints
Pricing
Admin Access
Support
Looks like most Cloud Database interactions are through the API, and rate limits are applied. You are also able to have up to 25 instances, at 150GB each.CloudRocket offers unlimited data storage if you have defined shard keys. Contact them if you need more than 200k operations/second.
Cloud Databases are charged per hour. Storage is charged at $0.75 per month.ObjectRocket has four different plans where you pay monthly, per-shard.
Some Cloud Database admin functions are exposed through their Control Panel (e.g. provision, resize) and others through API (e.e. backup) or client tools (e.g. import). See more on how to access the DB instance itself.
Rackspace provides lots of support options for Cloud Databases, including a ticketing system, community, help desk, and managed services.ObjectRocket support is done via email/chat/phone.
Salesforce.com (Database.com)
Recently made a standalone product after providing the backend to Salesforce.com for years, Database.com offers a feature-rich, metadata-driven database for cloud apps.
Type of Offering
Tech and Versions
Scalability
High Availability
Relational
Oracle underneath, but no exposure of direct capabilities. interact solely with Database.com interface.
Pod architecture designed to scale up and out automatically based on demand.
Geographically distinct data centers and near real-time replication between them.
Constraints
Pricing
Admin Access
Support
No upper limit on storage. Does impose API limits.
Free for 3 users, 100k records, 50k transactions. Pay for users, records, and transactions above that.
Manage Database.com via web console, Workbench, SOAP/REST API, and platform SDKs.
Offer a dev center, discussion boards, support tickets, and paid support plans.
Windows Azure
Microsoft has a set of database options that are similar in scope to what AWS offers. Great fit for shared databases between partners or as a companion to a web app running in Windows Azure.
Type of Offering
Tech and Versions
Scalability
High Availability
Relational and NoSQL
Windows Azure SQL Database runs SQL Server (2012).Windows Azure Table Storage provides a custom, schema-less repository.
SQL Database servers can be scaled up. Can also scale usage out through Federations to shard data.Azure Table data is sharded according to a partition key and can support up to 20k transactions per second.
For SQL Databases, backups are taken regularly. At least 3 replicas exist for each database.Azure Tables are replicated three times within a given data center.
Constraints
Pricing
Admin Access
Support
SQL Databases can be up to 150GB in size. SQL Databases don’t support the full feature set of SQL Server 2012.Azure Table entities can be up to 1MB in size, and tables/accounts can store up to 200TB of data.
Pay as you go for SQL Database instances. Different price for reserved capacity. Also pay for bandwidth consumption.Azure Table pricing is rolled up into “Storage” where you pay per GB/hr, and for bandwidth.
SQL Databases via REST API, web Management Console, or client tools.Azure Tables can be accessed via REST API (OData) and platform SDKs.
Whitepapers, documentation, community forums all free. Also offer paid support plans.
Summary
Clearly, there are a ton of choices when considering where to run a database in the cloud. You could choose to run a database yourself on a virtual machine (as all IaaS vendors promote), or move to a managed service where you give up some control, but get back time from offloading management tasks. Most of these services have straightforward web APIs, but do note that migration between each of them isn’t a one-click experience.
Are there other cloud databases that you like? Add them to the comments below!
Filed under: AWS, Cloud, Salesforce.com, SQL Azure, Windows Azure 
