Tuesday, October 18, 2011

Azure Storage


The Windows Azure storage services provide storage for binary and text data, messages, and structured data in Windows Azure

Option 1: Blob – Contains binary data: Blobs are organized by container.  Each storage account will be partitioned
by hierarchal containers which in turns have one or many blobs. We can store huge amount of data (text, audio, video, images etc…) with association of metadata like author details etc…

Two types of blobs:

·         Block blobs, which are optimized for streaming. Block blobs are comprised of blocks, each of which is identified by a block ID. Contain up to 200 GB.

·         Page blobs, which are optimized for random read/write operations. Page blobs are a collection of pages. Contain up to 1 TB.

A URL to refer to a blob includes the account name, the container name, and the blob name, as follows: http://myaccount.blob.core.windows.net/mycontainer/myblob

Sharing Policy: Container ACL access:

·         Full public read access: Container and blob data can be read via anonymous request.

·         Public read access for blobs only: Blob data within this container can be read via anonymous request, but container data is not available.

·         No public read access: Container and blob data can be read by the account owner only.


Windows Azure Drives: A Windows Azure drive acts as a local drive mounted on the file system and is accessible to code running in a role. The data written to a Windows Azure drive is stored in a page blob defined within the Windows Azure Blob service, and cached on the local file system.

Delivering High-Bandwidth Content with the Windows Azure Content Delivery Network:

This Windows Azure CDN feature enables customers to provide maximum bandwidth content to their users. As of now, Windows Azure CDN has 18 locations globally (United States, Europe, Asia, Australia and South America). As Windows Azure CDN caches Windows Azure blobs at strategically placed locations which is close to the location from which the request being made.  This is applicable to only blobs that are in public blob containers, which are available for anonymous access.


Option 2: Table - Entity Data Store: Tables store data as collections of entities. Table made up of rows / columns. Entities are similar to rows. A property is a name, typed-value pair, similar to a column. Don’t consider this as a RDBMS; it is more similar to ADO.NET Data services with reduced sub set including integer, string etc... It is mainly for store durable and scalable data structure that can be queried. It is equivalent of Amazon SimpleDB.

The operations are almost similar to that of a conventional database – tables. You can create, query and delete.

Option 3: Queue: It allows Web role instances to communicate asynchronously with Worker role instances. It acts as a reliable and persistent messaging between services.

In all the above options, Windows Azure storage keep the data replicated in many places and ensure data safety. Even one data copy being deleted or missed out can be available from another data copy from a data center. Isn’t this cool? Yes, this is nice feature which provides reliability and business continuity.

Moreover each of the data storage has a named URI (universal resource identifier) which can be accessible by any application including on cloud or on premises application through REST. REST defines an architectural style based on a set of constraints for building things the “Web” way. For more information on REST, refer my blog.


Check all my Azure related blogs: http://arunmvp.blogspot.com/search/label/Azure

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