To create a storage account, log in to the Windows Azure management portal at https://manage.windowsazure.com. After you log in to the portal you can quickly create a Storage Account by clicking on the large NEW icon at the bottom left hand of the portal.
From the expanding menu select the ‘Data Services’ option, then ‘Storage’ and finally, ‘Quick Create’.
You will now need to provide a name for your storage account in the URL textbox. This name is used as part of the URL for the service endpoint and so it must be globally unique. The portal will indicate whether the name is available whenever you pause or finish typing. Next, you select a location for your storage account by selecting one of the data center locations in the dropdown. This location will be the primary storage location for your data, or more simply, your account will reside in this Data Center. If you have created ‘affinity groups’, which is a friendly name of a collection of services you want to run in the same location, you will also see that in your drop down list. If you have more than one Windows Azure subscriptions related to your login address, you may also see a dropdown list to enable you to select the Azure subscription that the account will belong to.
All storage accounts are stored in triplicate, with transactionally-consistent copies in the primary data center. In addition to that redundancy, you can also choose to have ‘Geo Replication’ enabled for the storage account. ‘Geo Replication’ means that the Windows Azure Table and BLOB data that you place into the account will not only be stored in the primary location but will also be replicated in triplicate to another data center within the same region. So, if you select ‘West US’ for your primary storage location, your account will also have a triplicate copy stored in the East US data center. This mapping is done automatically by Microsoft and you can’t control the location of your secondary replication, but it will never be outside of a region so you don’t have to worry about your West US based account somehow getting replicated to Europe or Asia as part of the Geo Replication feature. Storage accounts that have Geo Replication enabled are referred to as geo redundant storage (GRS) and cost slightly more than accounts that do not have it enabled, which are called locally redundant storage (LRS).
Once you have selected the location and provided a name, you can click the ‘Create Storage Account’ action at the bottom of the screen. The Windows Azure portal will then generate the storage account for you within a few moments. When the account is fully created, you will see a status of Online. By selecting the new storage account in the portal, you can retrieve one of the access keys we will need in order to work with the storage account.
Click on the ‘Manage Access Keys’ at the bottom of the screen to display the storage account name, which you provided when you created the account, and two 512 bit storage access keys used to authenticate requests to the storage account. Whoever has these keys will have complete control over your storage account short of deleting the entire account. They would have the ability to upload BLOBs, modify table data and destroy queues. These account keys should be treated as a secret in the same way that you would guard passwords or a private encryption key. Both of these keys are active and will work to access your storage account. It is a good practice to use one of the keys for all the applications that utilize this storage account so that, if that key becomes compromised, you can use this dialog to regenerate the key you haven’t been using, then update the all the apps to use that newly regenerated key and finally regenerate the compromised key. This would prevent anyone abusing the account with the compromised key.
Your storage account is now created and we have what we need to work with it. For now, get a copy of the Primary Access Key by clicking on the copy icon next to the text box.
What Kind of BLOB is that?
Any file type can be stored in the Windows Azure BLOB Storage service, such as Image files, database files, text files, or virtual hard drive files. However, when they are uploaded to the service they are stored as either a Page BLOB or a Block BLOB depending on how you plan on using that file or the size of the file you need to work with.
Page BLOBs are optimized for random reads and writes so they are most commonly used when storing virtual hard drive files for virtual machines: In fact, the Page BLOB was introduced when the first virtual drive for Windows Azure was announced: the Windows Azure Cloud Drive (at the time they were known as Windows Azure X-Drives). Nowadays, the persisted disks used by Windows Azure Virtual Machine (Microsoft’s IaaS offering) also use the Page BLOB to store their data and Operating System drives. Each Page BLOB is made up of one or more 512-byte pages of data, up to a total size limit of 1 TB per file.
The majority of files that you upload would benefit from being stored as Block BLOBs, which are written to the storage account as a series of blocks and then committed into a single file. We can create a large file by breaking it into blocks, which can be uploaded concurrently and then then committed together into a single file in one operation. This provides us with faster upload times and better throughput. The client storage libraries manage this process by uploading files of less than 64 MB in size in a single operation, and uploading larger files across multiple operations by breaking down the files and running the concurrent uploads. A Block BLOB has a maximum size of 200 GB. For this article we will be using Block BLOBs in the examples.
