Azure Blob Storage – File, Object, and Data Lake Storage

Azure Blob Storage

Azure Blob Storage is a highly flexible object data storage solution in the cloud. It is designed to store massive amounts of data that are used in several different scenarios. The following list includes some common use cases for blob storage:

  • Storing unstructured data such as videos, images, and audio
  • Storing large amounts of data files that are used in big data solutions
  • Storing application log files
  • Storing data backups
  • Serving as an archive for historical data

Users can manage their Azure Blob Storage data in container objects. A container is like a directory in a file system and can store an unlimited amount of data. Users can create as many containers as they want in a single storage account, allowing them to organize data however they want. Containers can be accessed from anywhere in the world by appending the container name to the end of the Blob storage URI (for example, https://<storage-account-name>.blob.core.windows.net/<container_name>).

Containers store individual pieces of data as blob objects. New pieces of data can be categorized as one of the following blob types when they are uploaded to Azure Blob Storage:

  • Block blobs are optimized for storing large amounts of text and binary data. Data that is uploaded as a block blob is composed of block segments. A single block blob can contain up to 50,000 blocks, each one identified by a unique block ID. Existing block blobs can be modified by inserting, replacing, or deleting blocks. A single block blob can be approximately 190.7 TB.
  • Append blobs consist of blocks like block blobs but are optimized for append operations. When an append blob is modified, the additional data is appended to the end of the blob. Updating or deleting existing blocks is not supported. Append blobs are commonly used to store log files from virtual machines.
  • Page blobs store data as a collection of 512-byte pages, with a maximum blob size of 8 TB. They are optimized for random read and write operations. Writes to a page blob can overwrite up to 4 MB of pages in the blob. Random ranges of bytes can be read from or written to a page blob, making them ideal for storing OS and data disks for VMs and databases. For this reason, virtual data disks that serve Azure VMs are persisted as page blobs. Azure SQL Database also uses page blobs as the underlying storage for its databases. More information about page blobs and their uses cases can be found at https://docs.microsoft.com/en-us/azure/storage/blobs/storage-blob-pageblob-overview?tabs=dotnet.