As you may already know, you can create a snapshot of a virtual machine running on Azure when using managed disks.
While this is a useful capability, there was a limitation; when creating a snapshot you were creating a full snapshot, meaning the full disk was snapshotted, involving an increase in your storage cost.
Well, good news, you can now create incremental snapshot. This feature has been in preview for some time now and is now generally available.
Incremental snapshot generates a snapshot based on the delta/difference between 2 snapshots.
An incremental snapshot is always stored on the most cost-effective storage – standard HDD, irrespective of the storage type of the parent disk and on a Zone Redundant Storage (ZRS) for reliability.
Incremental snapshots are charged per Gb.
You can create incremental snapshots using either Azure Cli or Azure portal
sourceResourceId=$(az disk show -g <your resource group> -n <the disk to snapshot> –query ‘[id]’ -o tsv)
az snapshot create -g <your resource group> -n <name of the snapshot> -l <location> –source “$sourceResourceId” –incremental