What disk types are available in Azure?
Azure managed disks currently offers four disk types, three of which are generally available (GA) and one that is currently in preview. These four disk types each have their own appropriate target customer scenarios.
The following table provides a comparison of ultra solid-state-drives (SSD) (preview), premium SSD, standard SSD, and standard hard disk drives (HDD) for managed disks to help you decide what to use.
|Ultra SSD (preview)||Premium SSD||Standard SSD||Standard HDD|
|Scenario||IO-intensive workloads such as SAP HANA, top tier databases (for example, SQL, Oracle), and other transaction-heavy workloads.||Production and performance sensitive workloads||Web servers, lightly used enterprise applications and dev/test||Backup, non-critical, infrequent access|
|Disk size||65,536 gibibyte (GiB) (Preview)||32,767 GiB||32,767 GiB||32,767 GiB|
|Max throughput||2,000 MiB/s (Preview)||900 MiB/s||750 MiB/s||500 MiB/s|
|Max IOPS||160,000 (Preview)||20,000||6,000||2,000|
Ultra SSD (preview)
Azure ultra SSD (preview) deliver high throughput, high IOPS, and consistent low latency disk storage for Azure IaaS VMs. Some additional benefits of ultra SSD include the ability to dynamically change the performance of the disk, along with your workloads, without the need to restart your virtual machines. Ultra SSD are suited for data-intensive workloads such as SAP HANA, top tier databases, and transaction-heavy workloads. Ultra SSD can only be used as data disks. We recommend using premium SSDs as OS disks.
When you provision an ultra disk, you can independently configure the capacity and the performance of the disk. Ultra SSD come in several fixed sizes, ranging from 4 GiB up to 64 TiB, and feature a flexible performance configuration model that allows you to independently configure IOPS and throughput.
Some key capabilities of Ultra SSD are:
- Disk capacity: Ultra SSD capacity ranges from 4 GiB up to 64 TiB.
- Disk IOPS: Ultra SSD support IOPS limits of 300 IOPS/GiB, up to a maximum of 160 K IOPS per disk. To achieve the IOPS that you provisioned, ensure that the selected Disk IOPS are less than the VM IOPS. The minimum disk IOPS are 100 IOPS.
- Disk throughput: With ultra SSD, the throughput limit of a single disk is 256 KiB/s for each provisioned IOPS, up to a maximum of 2000 MBps per disk (where MBps = 10^6 Bytes per second). The minimum disk throughput is 1 MiB.
- Ultra SSDs support adjusting the disk performance attributes (IOPS and throughput) at runtime without detaching the disk from the virtual machine. Once a disk performance resize operation has been issued on a disk, it can take up to an hour for the change to actually take effect.
|Disk Size (GiB)||IOPS Caps||Throughput Cap (MBps)|
|1,024-65,536 (sizes in this range increasing in increments of 1 TiB)||160,000||2,000|
For ultra SSDs, each I/O operation less than or equal to 256 KiB of throughput is considered a single I/O operation. I/O operations larger than 256 KiB of throughput are considered multiple I/Os of size 256 KiB.
Preview scope and limitations
During preview, ultra SSD:
- Are supported in East US 2 in a single availability zone
- Can only be used with availability zones (availability sets and single VM deployments outside of zones will not have the ability to attach an ultra disk)
- Are only supported on ES/DS v3 VMs
- Are only available as data disks and only support 4k physical sector size
- Can only be created as empty disks
- Currently can only be deployed using Azure Resource Manager templates, CLI, and the python SDK.
- Does not yet support disk snapshots, VM images, availability sets, virtual machine scale sets, and Azure disk encryption.
- Does not yet support integration with Azure Backup or Azure Site Recovery.
- As with most previews, this feature should not be used for production workloads until general availability (GA).
If you would like to start using ultra SSDs, see our article on the subject: Enabling Azure ultra SSDs.
Azure premium SSDs deliver high-performance and low-latency disk support for virtual machines (VMs) with input/output (IO)-intensive workloads. To take advantage of the speed and performance of premium storage disks, you can migrate existing VM disks to Premium SSDs. Premium SSDs are suitable for mission-critical production applications. Premium SSDs can only be used with VM series that are premium storage-compatible.
To learn more about individual VM types and sizes in Azure for Windows, including which sizes are premium storage-compatible, see Windows VM sizes. To learn more about individual VM types and sizes in Azure for Linux, including which sizes are premium storage-compatible, see Linux VM sizes.
|Premium SSD sizes||P4||P6||P10||P15||P20||P30||P40||P50||P60||P70||P80|
|Disk size in GiB||32||64||128||256||512||1,024||2,048||4,096||8,192||16,384||32,767|
|IOPS per disk||Up to 120||Up to 240||Up to 500||Up to 1,100||Up to 2,300||Up to 5,000||Up to 7,500||Up to 7,500||Up to 16,000||Up to 18,000||Up to 20,000|
|Throughput per disk||Up to 25 MiB/sec||Up to 50 MiB/sec||Up to 100 MiB/sec||Up to 125 MiB/sec||Up to 150 MiB/sec||Up to 200 MiB/sec||Up to 250 MiB/sec||Up to 250 MiB/sec||Up to 500 MiB/sec||Up to 750 MiB/sec||Up to 900 MiB/sec|
When you provision a premium storage disk, unlike standard storage, you are guaranteed the capacity, IOPS, and throughput of that disk. For example, if you create a P50 disk, Azure provisions 4,095-GB storage capacity, 7,500 IOPS, and 250-MB/s throughput for that disk. Your application can use all or part of the capacity and performance. Premium SSD disks are designed to provide low single-digit millisecond latencies and target IOPS and throughput described in the preceding table 99.9% of the time.
For premium SSDs, each I/O operation less than or equal to 256 KiB of throughput is considered a single I/O operation. I/O operations larger than 256 KiB of throughput are considered multiple I/Os of size 256 KiB.
Azure standard SSDs are a cost-effective storage option optimized for workloads that need consistent performance at lower IOPS levels. Standard SSD offers a good entry level experience for those who wish to move to the cloud, especially if you experience issues with the variance of workloads running on your HDD solutions on premises. Compared to standard HDDs, standard SSDs deliver better availability, consistency, reliability, and latency. Standard SSDs are suitable for Web servers, low IOPS application servers, lightly used enterprise applications, and Dev/Test workloads. Like standard HDDs, standard SSDs are available on all Azure VMs.
|Standard SSD sizes||E4||E6||E10||E15||E20||E30||E40||E50||E60||E70||E80|
|Disk size in GiB||32||64||128||256||512||1,024||2,048||4,095||8,192||16,384||32,767|
|IOPS per disk||Up to 120||Up to 240||Up to 500||Up to 500||Up to 500||Up to 500||Up to 500||Up to 500||Up to 2,000||Up to 4,000||Up to 6,000|
|Throughput per disk||Up to 25 MiB/sec||Up to 50 MiB/sec||Up to 60 MiB/sec||Up to 60 MiB/sec||Up to 60 MiB/sec||Up to 60 MiB/sec||Up to 60 MiB/sec||Up to 60 MiB/sec||Up to 400 MiB/sec||Up to 600 MiB/sec||Up to 750 MiB/sec|
Standard SSDs are designed to provide single-digit millisecond latencies and the IOPS and throughput up to the limits described in the preceding table 99% of the time. Actual IOPS and throughput may vary sometimes depending on the traffic patterns. Standard SSDs will provide more consistent performance than the HDD disks with the lower latency.
For standard SSDs, each I/O operation less than or equal to 256 KiB of throughput is considered a single I/O operation. I/O operations larger than 256 KiB of throughput are considered multiple I/Os of size 256 KiB. These transactions have a billing impact.
Azure standard HDDs deliver reliable, low-cost disk support for VMs running latency-insensitive workloads. With standard storage, the data is stored on hard disk drives (HDDs). Latency, IOPS and Throughput of Standard HDD disks may vary more widely as compared to SSD-based disks. When working with VMs, you can use standard HDD disks for dev/test scenarios and less critical workloads. Standard HDDs are available in all Azure regions and can be used with all Azure VMs.
|Standard Disk Type||S4||S6||S10||S15||S20||S30||S40||S50||S60||S70||S80|
|Disk size in GiB||32||64||128||256||512||1,024||2,048||4,095||8,192||16,384||32,767|
|IOPS per disk||Up to 500||Up to 500||Up to 500||Up to 500||Up to 500||Up to 500||Up to 500||Up to 500||Up to 1,300||Up to 2,000||Up to 2,000|
|Throughput per disk||Up to 60 MiB/sec||Up to 60 MiB/sec||Up to 60 MiB/sec||Up to 60 MiB/sec||Up to 60 MiB/sec||Up to 60 MiB/sec||Up to 60 MiB/sec||Up to 60 MiB/sec||Up to 300 MiB/sec||Up to 500 MiB/sec||Up to 500 MiB/sec|
For Standard HDDs, each IO operation is considered as a single transaction, regardless of the I/O size. These transactions have a billing impact.
When using managed disks, the following billing considerations apply:
- Disk type
- managed disk Size
- Outbound data transfers
- Number of transactions
Managed disk size: managed disks are billed on the provisioned size. Azure maps the provisioned size (rounded up) to the nearest offered disk size. For details of the disk sizes offered, see the previous tables. Each disk maps to a supported provisioned disk size offering and is billed accordingly. For example, if you provisioned a 200 GiB Standard SSD, it maps to the disk size offer of E15 (256 GiB). Billing for any provisioned disk is prorated hourly by using the monthly price for the Premium Storage offer. For example, if you provisioned an E10 disk and deleted it after 20 hours, you're billed for the E10 offering prorated to 20 hours. This is regardless of the amount of actual data written to the disk.
Snapshots: Snapshots are billed based on the size used. For example, if you create a snapshot of a managed disk with provisioned capacity of 64 GiB and actual used data size of 10 GiB, the snapshot is billed only for the used data size of 10 GiB.
For more information on snapshots, see the section on snapshots in the managed disk overview.
Outbound data transfers: Outbound data transfers (data going out of Azure data centers) incur billing for bandwidth usage.
Transactions: You're billed for the number of transactions that you perform on a standard managed disk. For standard SSDs, each I/O operation less than or equal to 256 KiB of throughput is considered a single I/O operation. I/O operations larger than 256 KiB of throughput are considered multiple I/Os of size 256 KiB. For Standard HDDs, each IO operation is considered as a single transaction, regardless of the I/O size.
For detailed information on pricing for Managed Disks, including transaction costs, see Managed Disks Pricing.
Ultra SSD VM reservation fee
Azure VMs have the capability to indicate if they are compatible with ultra SSD. An ultra disk compatible VM allocates dedicated bandwidth capacity between the compute VM instance and the block storage scale unit to optimize the performance and reduce latency. Adding this capability on the VM results in a reservation charge that is only imposed if you enabled ultra disk capability on the VM without attaching an ultra disk to it. When an ultra disk is attached to the ultra disk compatible VM, this charge would not be applied. This charge is per vCPU provisioned on the VM.
Refer to the Azure Disks pricing page for ultra disk Disks pricing details.
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