Blob storage services
For customers needing to store large sets of unstructured data, Blob storage offers an attractive and scalable answer. The types of data that can be retained in Blob storage are—documents, photos, music, videos, blogs, file backup, databases, images and text for web applications, big data, or configuration data for cloud applications.
Containers offer a useful way to assign security policies to sets of objects; each blob is assigned a container. A storage account can hold indefinite containers; a container may contain an indefinite number of blobs. The only restriction is the 500 TB capacity limit of the storage account.
There are three types of blobs:
- Block blobs: Block blobs are utilized for streaming and storing cloud objects. They are best used for storing documents, media files, backups, and so on.
- Append blobs: Block blobs are used for streaming and storing; append blobs fulfill the same task with the addition that they are optimized for append operations. Updating an append blob can only be done by adding a new block to the end. An append blob's field of application consists of logging, in which data has to be written to the end of the blob.
- Page blobs (disks): The third type of blob is the page blob. In most cases, page blobs are used to store Infrastructure as a Service (IaaS) disks. They support random writes. This means that an Azure IaaS VM virtual hard disk (VHD) is stored as a page blob.
In the cases where downloading data over the wire to Blob storage is unrealistic, for example for large datasets, the customer is able to send a hard drive directly to Microsoft, where the data gets directly imported to or exported from the datacenter. In Azure, blobs are stored in containers. These containers are the upper most element that needs to be used to store files as blobs.
In Azure IaaS, there will be a VHDs container created when you deploy an image from the gallery. These containers hold the VHD files for the VMs as page blobs, and also hold status blobs as block blobs.
Azure Storage blobs have access types; those access types define how your blobs can be accessed publicly:
