Updated 25 October 2026 · Published by Zoorik
Thin provisioning in storage creates a volume that takes up space only as you write data. You still set its full size when you create it. Its share of the storage pool starts small and grows with your data.
Thin provisioning vs thick provisioning
- Thick provisioning, which Azure Local calls fixed, reserves the full size up front. A thick disk still works when the pool is full.
- Thin provisioning takes space only as needed, and thin volumes can add up to more than the pool holds.
- By default, Azure Local alerts you when over 70% of the pool is used.
A 10 GB virtual disk
In Microsoft’s example, you create a 10 GB virtual disk. With thick provisioning, all 10 GB is set aside at once, and other virtual machines (VMs) can’t share it.
A thin provisioned disk takes only what it needs, then grows.
Why it matters for your bill
Azure managed disks and Amazon EBS volumes bill the size you provision, not the data you write. So an empty GiB costs the same as a full one.
- In Microsoft’s billing example, a 1 TiB Standard SSD holds 120 GiB. It still bills as 1 TiB.
- An Azure managed disk bills its full size from first use.
- Amazon EBS bills the GB you provision each month.
Amoeba moves a VM’s data disks onto one pool sized to your data, then rightsizes it autonomously. The free assessment works out your own figure.
Sizing disks to their data is rightsizing, covered in Azure disk cost optimization.
Read next: Azure disk cost optimization
Sources: Microsoft Learn, “Storage thin provisioning in Azure Local, version 23H2” (opens in a new tab); Microsoft Learn, “Microsoft Azure VMware Solution FAQ” (opens in a new tab); Microsoft Learn, “Understand Azure Disk Storage billing” (opens in a new tab); AWS, “Amazon EBS pricing” (opens in a new tab).