This is a very frequent question that I get in my job and I thought I would provide some clarity on this on my blog.
Azure Premium Storage performance is determined by two factors:
- Disk Size
- VM Size
Choosing the right disk size
Currently (April 2016) there are three premium storage disk sizes. If you choose to create a disk with a different size, your disk will be charged for and support the performance targets of the next tier up. This is due to the fact that Azure needs to allocate a whole SSD of the next size tier to host your disk image.
Premium Storage Disk Type | P10 | P20 | P30 |
Disk size | 128 GiB | 512 GiB | 1024 GiB (1 TB) |
Max IOPS per disk | 500 | 2300 | 5000 |
Max throughput per disk | 100 MB per second | 150 MB per second | 200 MB per second |
Max number of disks per storage account |
280 | 140 | 35 |
Choosing the right VM size
Depending on what premium storage VM you choose in conjunction with your premium disks, you may impose a limit on the performance that you can achieve.
For example: A DS1_v2 instance is limited to 48 MB per second throughput and 3,200 IOPS. This means that even with a P30 disk attached to it, it will never achieve 200 MB per second or 5,000 IOPS.
Size | CPU cores | RAM | Temporary |
Max. data disks | Max. disk IOPS & bandwidth | Max network bandwidth |
Standard_DS1_v2 | 1 | 3.5 GB | 7 GB | 2 | 3,200 48 MB per second | moderate |
Standard_DS2_v2 | 2 | 7 GB | 14 GB | 4 | 6,400 96 MB per second | high |
Standard_DS3_v2 | 4 | 14 GB | 28 GB | 8 | 12,800 192 MB per second | high |
Standard_DS4_v2 | 8 | 28 GB | 56 GB | 16 | 25,600 384 MB per second | high |
Standard_DS5_v2 | 16 | 56 GB | 112 GB | 32 | 50,000 768 MB per second | high |
Standard_DS11_v2 | 2 | 14 GB | 28 GB | 4 | 6,400 96 MB per second | high |
Standard_DS12_v2 | 4 | 28 GB | 56 GB | 8 | 12,800 192 MB per second | high |
Standard_DS13_v2 | 8 | 56 GB | 112 GB | 16 | 25,600 384 MB per second | high |
Standard_DS14_v2 | 16 | 112 GB | 224 GB | 32 | 50,000 768 MB per second | very high |
Source and full table for all premium storage machine sizes: https://azure.microsoft.com/en-us/documentation/articles/virtual-machines-windows-sizes/#standard-tier-ds-series