Azure Premium Storage: Premium Disks, File and Blob Storage

What is Azure Premium Storage?

Microsoft Azure offers two service tiers for its storage services: Standard Storage and Premium Storage. The Premium tier stores data on modern solid state drives (SSDs), while the Standard tier uses hard disk drives (HDDs).

Premium Azure storage is appropriate for virtual machines and workloads that need low latency and high I/O performance, for example transactional databases or big data systems. Standard storage, which is offered at lower cost, can be used for less demanding workloads.

In this article, you will learn:

Azure Premium Disk Storage

Azure managed disks are block storage attached to virtual machines. They are similar to a hard drive connected to a bare-metal server, but virtualized. Users can specify the disk size they need, select a service tier—Standard, Premium, or Ultra—and provision a disk.

Premium Managed Disks

Azure Premium Managed Disks are based on solid state drives (SSDs), which provide single-digit millisecond latency, and are guaranteed to provide specific levels of IOPS and throughput 99.9% of the time.

The following table shows the IOPS and throughput provided by Azure’s Premium Disks. For disks P1-P20, the disk is initially provisioned with a certain level of IOPS and throughput, and the disk can “burst” to a higher level if needed.

Azure Premium Managed DisksSource: Azure

Bursting works as follows: 

  • Each disk has a “burst bucket” of credits
  • Credits are accumulated every time disk traffic is below the provisioned target
  • Whenever the disk needs IOPS or throughput above the provisioned target, it “bursts” to provide higher performance, and credits are deducted

Ultra Managed Disks

Ultra Disks provide more flexibility than Premium Disks, because they let you independently select the disk capacity and the required performance. You can select the following features:

  • Capacity between 4 GB and 64 TB.
  • IOPS between 300 IOPS/GB and 160,000 IOPS per disk
  • Throughput between 256 KB/s and 2,000 MB/s for each provisioned IOPS

In addition, Ultra Disks make it possible to change performance attributes on the fly, without detaching the disk or restarting the virtual machine. Resize operations can take up to an hour to complete.

Azure Block Blob Premium Storage

Azure Blob storage, also known as Block Blob storage, is an object storage service which can store unlimited amounts of unstructured data. Block blobs can store text and binary data—they are made up of blocks of data that can be managed individually.

For demanding workloads, Azure offers Premium Blob Storage, which provides:

  • Lower latency for accessing blobs and block blobs
  • Consistent, guaranteed response times for both read and write operations
  • Better performance for smaller blob sizes

To take advantage of the reduced latency, the application must run on a virtual machine in the same Azure region as the storage account.

Premium Blob Storage also provides:

  • Locally-Redundant Storage  (LRS)—replicates data three times within an Azure data center, providing durability of 99.999999999% (11 nines).
  • High-Throughput Block Blobs (HTBB)—enables very fast write performance when ingesting blobs over 256KB in size.
  • Lower transaction cost—compared to the Hot Blob Storage tier, the Premium tier has higher storage costs, but costs less for writes and other operations, making it cheaper in some cases for workloads with high throughputs.

Azure Files Premium

Azure Files provides managed, cloud-based file shares which can be accessed via common file protocols—the Windows Server Message Block (SMB) protocol and Linux Network File System (NFS) protocol. Azure file shares can be mounted by cloud VMs or machines running on-premises.

Azure Files provides a Premium tier that stores file shares on solid state drives (SSD), with single-digit millisecond latency.

Azure Files Premium uses a provisioned capacity model. You specify in advance how much storage you need, and you pay per provisioned capacity, not per actual capacity used. You can, however, scale the provisioned capacity up and down at will. 

The performance level provided by Azure Files Premium is directly related to the number of provisioned GBs of storage. As you can see in the table below, the baseline number of IOPS is 400 + 1 per provisioned GB. Beyond that, disks are able to “burst” to provide higher performance.

Azure Files Premium IOPSSource: Azure

Bursting works as follows:

  • Premium file shares can burst up to 4,000 IOPS or 3X the baseline IOPS (whichever is higher)
  • Bursting uses a credit system—the file share accumulates credits when it uses less than the baseline IOPS, and uses credits when it needs to burst above baseline performance
  • The burst limit is not guaranteed—Azure performs bursting for file shares on a “best effort” basis
  • Bursting duration can be up to 60 minutes

Azure Premium Storage Q&A

What Type of Storage Offers the Lowest Latency in Azure?

Azure Premium Storage offers lower latency, compared to Standard Storage, because it is based on faster SSD disk drives. For blob storage, Azure advertises latency of single-digit milliseconds for Premium Storage, and milliseconds for Standard Storage (hot or cool tier).

What is a Premium SSD in Azure?

Azure Premium Storage is a tier provided across all storage services, which stores data on fast solid state drives (SSD). This can support workloads that require high throughout and a large number of I/O operations per second.

You can use SSD Managed Disks directly, attaching them to Azure VMs. Alternatively, you can use the Premium tier on storage services like blob storage, and ensure your data is stored on SSDs behind the scenes.

What is the Difference Between SSD and HDD in Azure?

The difference between SSD and HDD drives in Azure is that SSD storage equipment is provided at a higher cost, as part of the Premium storage tier. For example, Premium Managed Disks (SSD) start from $0.6 per month for 4GB, while Standard Managed Disks (HDD) start from $0.3 per month for 4GB. SSD provides higher performance that can support mission critical and high throughput workloads.

Optimized Azure File Storage with Azure NetApp Files

Azure NetApp Files is another file storage alternative from Microsoft Azure built on NetApp technology, giving you enterprise file share capabilities that can support even your core business applications.

Get enterprise-grade data management and storage to Azure so you can manage your workloads and applications with ease, and move all of your file-based applications to the cloud.

Azure NetApp Files solves availability and performance challenges for enterprises that want to move mission-critical applications to the cloud, including workloads like HPC, SAP, Linux, Oracle and SQL Server workloads, Windows Virtual Desktop, and more.

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