Azure blob storage
Azure Blob Storage supports three different types of blob:
- Block blobs. A block blob is handled as a set of blocks. Each block can vary in size, up to 100 MB. A block blob can contain up to 50,000 blocks, giving a maximum size of over 4.7 TB. Block blobs are best used to store discrete, large, binary objects that change infrequently.
- Page blobs. A page blob is organized as a collection of fixed size 512-byte pages. A page blob is optimized to support random read and write operations; you can fetch and store data for a single page if necessary. A page blob can hold up to 8 TB of data. Azure uses page blobs to implement virtual disk storage for virtual machines.
- Append blobs. An append blob is a block blob optimized to support append operations. You can only add blocks to the end of an append blob; updating or deleting existing blocks isn't supported. Each block can vary in size, up to 4 MB. The maximum size of an append blob is just over 195 GB.
Blob storage provides three access tiers, which help to balance access latency and storage cost:
- The Hot tier is the default. You use this tier for blobs that are accessed frequently. The blob data is stored on high-performance media.
- The Cool tier has lower performance and incurs reduced storage charges compared to the Hot tier. Use the Cool tier for data that is accessed infrequently.
- The Archive tier provides the lowest storage cost, but with increased latency. The Archive tier is intended for historical data that mustn't be lost, but is required only rarely. Blobs in the Archive tier are effectively stored in an offline state. Typical reading latency for the Hot and Cool tiers is a few milliseconds, but for the Archive tier, it can take hours for the data to become available. To retrieve a blob from the Archive tier, you must change the access tier to Hot or Cool.
Azure DataLake Storage Gen2
Azure Data Lake Store (Gen1) is a separate service for hierarchical data storage for analytical data lakes, often used by so-called big data analytical solutions that work with structured, semi-structured, and unstructured data stored in files. Azure Data Lake Storage Gen2 is a newer version of this service that is integrated into Azure Storage; enabling you to take advantage of the scalability of blob storage and the cost-control of storage tiers, combined with the hierarchical file system capabilities and compatibility with major analytics systems of Azure Data Lake Store.
To create an Azure Data Lake Store Gen2 files system, you must enable the Hierarchical Namespace option of an Azure Storage account. You can do this when initially creating the storage account, or you can upgrade an existing Azure Storage account to support Data Lake Gen2. Be aware however that upgrading is a one-way process – after upgrading a storage account to support a hierarchical namespace for blob storage, you can’t revert it to a flat namespace.
Azure Files
Azure Files is essentially a way to create cloud-based network shares, such as you typically find in on-premises organizations to make documents and other files available to multiple users. By hosting file shares in Azure, organizations can eliminate hardware costs and maintenance overhead, and benefit from high availability and scalable cloud storage for files.
Azure Files enables you to share up to 100 TB of data in a single storage account. This data can be distributed across any number of file shares in the account. The maximum size of a single file is 1 TB
Currently, Azure File Storage supports up to 2000 concurrent connections per shared file.
Azure File Storage offers two performance tiers. The Standard tier uses hard disk-based hardware in a datacenter, and the Premium tier uses solid-state disks. The Premium tier offers greater throughput, but is charged at a higher rate.
Azure Files supports two common network file sharing protocols:
- Server Message Block (SMB) file sharing is commonly used across multiple operating systems (Windows, Linux, macOS).
- Network File System (NFS) shares are used by some Linux and macOS versions. To create an NFS share, you must use a premium tier storage account and create and configure a virtual network through which access to the share can be controlled.