Microsoft have recently announced the release of Azure Premium SSD V2 disks as generally available for select regions, but what does this mean for you?
Azure Premium v2 disks uncouple IOPs and throughput metrics from disk size, meaning you can adjust the IOPS, throughput, and capacity according to your workload needs. Premium SSD v2 disks are designed to handle performance-sensitive and general-purpose workloads that require low average read and write latency, high IOPS, and high throughput. Whereas with Azure Premium and Azure Ultra disks, IOPS and throughput are fixed by disk size. This can make Premium SSD V2 disks an efficient and cost-effective option for running and scaling transaction-intensive workloads.
Achieving High IO loads with Premium SSD
Assuming you have a highly transactional 100GB database generating a sustained load of 10,000 IOPs with a throughput of 200MB / sec and an appropriate compute configuration to support this. To achieve this with Premium SSD disks would require 4 x P20 disks or 2 x P30 disks presented to your compute and striped using a volume set. This however would also see overkill in both available space and data transfer.
| 4 x P20 | 2 x P30 | |
| Size | 2,048GB | 2,048GB |
| IOPs | 9,200 IOPs | 10,000 IOPs |
| Throughput | 600 MB/sec | 400 MB/sec |
Note that the above configuration only takes into account performance and does not address any concerns such as redundancy and data protection.
Achieving High IO loads with Premium SSD V2 disks
As V2 disks are configurable across all 3 parameters, the allocated disk is much more aligned with the need of the workload. Also, all three parameters can be adjusted as workload parameters change through growth. For the example above, a Premium SSD V2 disk would look like:
| Required | Included | Additional | |
| Size | 100GB | n/a | n/a |
| IOPs | 10,000 | 3,000 | 7,000 |
| Throughput (MB/sec) | 200 | 125 | 75 |
According to the Microsoft article for Managed Disks Pricing, this configuration would represent a significant saving in cost for the disk as well as reduced overhead. Like the previous example, this example only takes into account performance and does not address any concerns such as redundancy and data protection.
Current limitations of Azure Premium SSD v2 disks
As of the writing of this article, there are some limitations to Premium v2 disks. Firstly, they are only available in the following regions:
- US East
- West Europe
The other limiting factors are:
- Disks are only available on Locally Redundant Storage.
- Snapshots are not supported
- Encryption capabilities are very limited
- Azure Backup / Site Recovery aren’t supported for VM’s with V2 disks
I would expect these limitations to change over time.
Why Azure Premium SSD v2 disks should be on your radar
Current Premium SSD Disk configurations are fixed in their Size/ IOPs/Throughput ratios and therefore require additional overhead and creativity to achieve specific workloads for high performing systems and usually come with wasted resources that you are paying for.
With the introduction of Premium SSD V2 disks, you can have better control over your configuration and therefore only pay for what you need. As reductions in operating costs and management overhead is something that benefits all users and should be something watched for in your Azure deployment region.