Monday, March 17, 2008 at 4:39AM

Highly available and highly scalable.



Targeted at applications that can tolerate high internet latencies. Primarily read-mostly data sets "storing data that is naturally partitionable into disjoint data sets requiring little or no cross-correlations."



Pricing isn't yet available.



No announced SLA, though you will be notified of downtime.



Access is via REST or SOAP.



Data is redundantly stored and backed up.



Geo-redundant data copies are maintained. Data is stored in large storage clusters in various Microsoft data centers located across North America. Plan to expand to more areas later.



The data model is flexible. No schemas required. "Simply add new attributes to your data set when needed, and the system will automatically store, index, and query your data accordingly."



String, numeric, datetime, and boolean data type are supported. All attributes are indexed.



The data model is: Customer { SSDS account (1..N) { Authority (1..N) { Container (0..N) { Entity (0..N)

- Authorities give billing entities a way to organize their usage for accounting, security and co-location purposes. All containers under a single authority are provisioned within the same data center. As such authorities are the unit of geo-scale and geo-location. For example: Seattle or San Francisco.

- Containers create contexts and scope for entity storage and query. For example, within its authorities, operations could choose to assign each member their own container, intended to contain a set of personal data for that member. Containers are the unit of consistency in the Microsoft SSDS service. For example: Autos for Sale, Services Offered.

- Entities are the fundamental unit of storage in the system. Entities are a bag of scalars with no enforced type. For example, an individual member‟s jobs, educational institutions, contacts, recommendations, etc. could all be modeled as entities.



Data manipulation operations include:

- Creation and deletion of containers. There are no updatable container properties.

- Creation, replacement, and deletion of entities.

- Retrieval of a single container in a serialized format.

- Retrieval of a single entity in a serialized format.



A text based query language is supported that follow the LINQ pattern for C#. Only complete entities are returned. For example:



To query addressed to a container to retrieve all entities in that container having a “City” property equal to “Seattle” and a “State” property equal to “WA” would be written as follows:



from e in entities

where e[“City”] == “Seattle” && e[“State”] == “WA”

select e





Resource queries are supported. This URI returns all the entities in that container: http://mydomain.ssds.microsoft.com/ChildrensBooksContainer1



Customers will be able to associate entities with blobs which could be accessed as URL addressable resources.



SSDS is not just a hosted version of SQL Server. It's SQL Server deconstructed, running on blade servers with SATA drives.



A local on-premise version of SSDS will also be available to "allow users to better synchronize between the enterprise and the cloud, especially when handling reporting, analytics and business-intelligence tasks."





Not sure if you can do a full text search on a string property.



Not sure how large attributes can be. Should I store my 25MB documents as a string field so it can be searched? Or is that too expensive? Or is it even supported?



Where Microsoft is behind Amazon is that they don't have EC2 and S3. Microsoft is having you traverse the internet for each database access. Now let''s say you have chunks of large storage stored off in a storage cloud. That's a lot of overhead.



A major benefit of AWS is the free bandwidth and higher performance within the AWS cloud.

If your application is completely hosted within the cloud the only slow part is from the server to the user's browser.



All-in-all SSDS seems very comparable to and competitive with SimpleDB. Hard to say without solid pricing information. But it will be interesting to see how Microsoft's cloud strategy evolves and how we can all benefit from the competition.



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