VM Sizes and Series

Choosing the right VM size is one of the most important decisions when working with Azure Virtual Machines. Azure offers hundreds of VM sizes grouped into families, each optimised for different workload types. Selecting the correct size ensures you get the performance you need without overspending.

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Understanding VM Size Names

Azure VM sizes follow a naming convention that encodes the family, sub-family, vCPU count, and features:

Standard_D4s_v5
│        ││ │
│        ││ └─ Version (v5 = 5th generation)
│        │└── Feature flags (s = Premium Storage capable)
│        └─── vCPU count (4 vCPUs)
│
└─ Family (D = General Purpose)

Common Feature Flags

Flag	Meaning
s	Premium Storage capable
d	Local temp disk (NVMe)
a	AMD processor
p	ARM-based (Ampere) processor
l	Low memory (less RAM per vCPU)
i	Isolated (dedicated physical host)
b	Block storage performance

For example, Standard_D4ads_v5 is a general-purpose VM with 4 vCPUs, an AMD processor, a local temp disk, and Premium Storage support.

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VM Families