Microsoft Explains Azure Disks’ New SSD Bursting Feature

Azure Disks SDD bursting capabilities are available on a total of eight plans, with a max bandwidth of up to 170 MiB/s and bust IOPS of 3,500.

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has expanded on the bursting capabilities it announced for Azure Storage at Ignite. In new documentation, it detailed the various states, specifications, and example scenarios.

According to the company, bursting lets eligible disks achieve up to 30x the provisioned performance target to better handle spiky workloads. This should help in workloads that have unpredictable disk usage and improve overall performance.

warned in its documentation and supporting blog post that this functionality will only be available on its premium SSDs. It will also work on a “best effort” credit-based system. Essentially, you get credits when the traffic is below your provisioned target, which are consumed when it exceeds that through burst.

As well as spiky workloads, Microsoft says this will help with the boots. During startup, the OS disk may be used at a higher rate than what's provisioned, and burst could also reduce application launch time.

“With this preview release, we lower the entry cost of adoption with smaller disk sizes and make our disk offerings more performant leveraging burst support,” said Azure Storage program manager Yuemin Lu in the blog post.

Those smaller burst capable disks are P1, P2, and P3, bringing the total number of burst capable disk types to eight. All support max bursts of up to 170MiB for up to 30 minutes at peak. Burst IOPS goes up to 3,500 on each disk. Here are the full stats:

Burst Capable Disks Disk Size Provisioned IOPS per disk Provisioned Bandwidth per disk Max Burst IOPS per disk Max Burst Bandwidth per disk Max Burst Duration at Peak Burst Rate
P1 – New 4 GiB 120 25 MiB/sec 3,500 170 MiB/sec 30 mins
P2 – New 8 GiB 120 25 MiB/sec 3,500 170 MiB/sec 30 mins
P3 – New 16 GiB 120 25 MiB/sec 3,500 170 MiB/sec 30 mins
P4 32 GiB 120 25 MiB/sec 3,500 170 MiB/sec 30 mins
P6 64 GiB 240 50 MiB/sec 3,500 170 MiB/sec 30 mins
P10 128 GiB 500 100 MiB/sec 3,500 170 MiB/sec 30 mins
P15 256 GiB 1,100 125 MiB/sec 3,500 170 MiB/sec 30 mins
P20 512 GiB 2,300 150 MiB/sec 3,500 170 MiB/sec 30 mins

Unfortunately, you'll only be able to use this function currently in the Azure West Central US region. Microsoft has plans for a wider rollout soon, though, and the good news is that it'll be enabled by default in all regions.