B-series burstable virtual machine sizes

Applies to: ✔️ Linux VMs ✔️ Windows VMs ✔️ Flexible scale sets ✔️ Uniform scale sets

The B-series VMs can be deployed on a variety of hardware types and processors, so competitive bandwidth allocation is provided. B-series run on the 3rd Generation Intel® Xeon® Platinum 8370C (Ice Lake), the Intel® Xeon® Platinum 8272CL (Cascade Lake), the Intel® Xeon® 8171M 2.1 GHz (Skylake), the Intel® Xeon® E5-2673 v4 2.3 GHz (Broadwell), or the Intel® Xeon® E5-2673 v3 2.4 GHz (Haswell) processors. B-series VMs are ideal for workloads that do not need the full performance of the CPU continuously, like web servers, proof of concepts, small databases and development build environments. These workloads typically have burstable performance requirements. To determine the physical hardware on which this size is deployed, query the virtual hardware from within the virtual machine. The B-series provides you with the ability to purchase a VM size with baseline performance that can build up credits when it is using less than its baseline. When the VM has accumulated credits, the VM can burst above the baseline using up to 100% of the vCPU when your application requires higher CPU performance.

The B-series comes in the following VM sizes:

Azure Compute Unit (ACU): Varies*
Premium Storage: Supported
Premium Storage caching: Not Supported
Live Migration: Supported
Memory Preserving Updates: Supported
VM Generation Support: Generation 1 and 2
Accelerated Networking: Supported**
Ephemeral OS Disks: Supported
Nested Virtualization: Not Supported

*B-series VMs are burstable and thus ACU numbers will vary depending on workloads and core usage.
**Accelerated Networking is only supported for Standard_B12ms, Standard_B16ms and Standard_B20ms.

Size vCPU Memory: GiB Temp storage (SSD) GiB Base CPU Performance of VM (%) Initial Credits Credits banked/hour Max Banked Credits Max data disks Max uncached disk throughput: IOPS/MBps Max burst uncached disk throughput: IOPS/MBps1 Max NICs
Standard_B1ls2 1 0.5 4 5 30 3 72 2 160/10 4000/100 2
Standard_B1s 1 1 4 10 30 6 144 2 320/10 4000/100 2
Standard_B1ms 1 2 4 20 30 12 288 2 640/10 4000/100 2
Standard_B2s 2 4 8 20 60 24 576 4 1280/15 4000/100 3
Standard_B2ms 2 8 16 30 60 36 864 4 1920/22.5 4000/100 3
Standard_B4ms 4 16 32 22.5 120 54 1296 8 2880/35 8000/200 4
Standard_B8ms 8 32 64 17 240 81 1994 16 4320/50 8000/200 4
Standard_B12ms 12 48 96 17 360 121 2908 16 4320/50 16000/400 6
Standard_B16ms 16 64 128 17 480 162 3888 32 4320/50 16000/400 8
Standard_B20ms 20 80 160 17 600 202 4867 32 4320/50 16000/400 8

1 B-series VMs can burst their disk performance and get up to their bursting max for up to 30 minutes at a time.

2 B1ls is supported only on Linux

Other sizes and information

Pricing Calculator: Pricing Calculator

More information on Disks Types: Disk Types

Next steps

Learn more about how Azure compute units (ACU) can help you compare compute performance across Azure SKUs.