| title | Resize an Azure Elastic SAN and its volumes |
|---|---|
| description | Learn how to increase or decrease the size of an Azure Elastic SAN and its volumes with the Azure portal, Azure PowerShell module, or Azure CLI. |
| author | roygara |
| ms.service | azure-elastic-san-storage |
| ms.topic | how-to |
| ms.date | 01/13/2026 |
| ms.author | rogarana |
| ms.custom | devx-track-azurecli, devx-track-azurepowershell |
This article explains how to increase or decrease the size of an Elastic SAN and an individual volume.
To increase the size of your volumes, first increase the size of your Elastic SAN. To decrease the size of your SAN, make sure your volumes don't use the extra size and then change the size of the SAN.
# You can either update the base size or the additional size.
# This command updates the base size, to update the additional size, replace -BaseSizeTiB $newBaseSizeTib with -ExtendedCapacitySizeTib $newExtendedSizeTib
Update-AzElasticSan -ResourceGroupName $resourceGroupName -Name $sanName -BaseSizeTib $newBaseSizeTib
# You can either update the base size or the additional size.
# This command updates the base size, to update the additional size, replace -base-size-tib $newBaseSizeTib with -extended-capacity-size-tib $newExtendedCapacitySizeTib
az elastic-san update -e $sanName -g $resourceGroupName --base-size-tib $newBaseSizeTib
You can automatically scale up your SAN by specific increments until a specified maximum size. The capacity increments have a minimum of 1 TiB, and you can only set up an autoscale policy for additional capacity units. So when autoscaling, your performance doesn't automatically scale up as your storage does. Here's an example of setting an autoscale policy by using Azure CLI:
az elastic-san update -n mySanName -g myVolGroupName --auto-scale-policy-enforcement "Enabled" --unused-size-tib 20 --increase-capacity-unit-by-tib 5 --capacity-unit-scale-up-limit-tib 150
Running that example command sets the following policy on the SAN: If your SAN's unused capacity (free space) is less than 20 TiB, increase the SAN's additional capacity by 5 TiB, until its unused capacity is at least 20 TiB. Don't allow the SAN's total capacity to exceed 150 TiB.
You can't use an autoscale policy to scale down. To reduce the size of your SAN, follow the manual process in the previous section. If you configured an autoscaling policy, disable it before reducing the size of your SAN.
For CLI, ensure you're using a version that's 1.2.0b1 or higher of the elastic-san extension. For PowerShell, ensure you're using a version that's 1.2.1 or higher of the Az.ElasticSan module.
The following script can be run to enable an autoscale policy for an existing Elastic SAN.
# Define some variables.
autoscalePolicyEnforcement = "Enabled" # Whether autoscale is enabled or disabled at the SAN level
unusedSizeTiB = "<UnusedSizeTiB>" # Unused capacity on the SAN
increaseCapacityUnit = "<IncreaseCapacityUnit>" # Amount by which the SAN will scale up if the policy is triggered
capacityUnitScaleUpLimit = "<CapacityUnitScaleUpLimit>" # Maximum capacity until which scale up operations will occur
Update-AzElasticSan -ResourceGroupName myresourcegroup -Name myelasticsan -AutoScalePolicyEnforcement $autoscalePolicyEnforcement -UnusedSizeTiB $unusedSizeTiB -IncreaseCapacityUnitByTiB $increaseCapacityUnit -CapacityUnitScaleUpLimitTiB $capacityUnitScaleUpLimit
# Define some variables.
autoscalePolicyEnforcement = "Enabled" # Whether autoscale is enabled or disabled at the SAN level
unusedSizeTiB = "<UnusedSizeTiB>" # Unused capacity on the SAN
increaseCapacityUnit = "<IncreaseCapacityUnit>" # Amount by which the SAN will scale up if the policy is triggered
capacityUnitScaleUpLimit = "<CapacityUnitScaleUpLimit>" # Maximum capacity until which scale up operations will occur
az elastic-san update -n $sanName -g $resourceGroupName --auto-scale-policy-enforcement $autoscalePolicyEnforcement --unused-size-tib $unusedSizeTiB --increase-capacity-unit-by-tib $increaseCapacityUnit --capacity-unit-scale-up-limit-tib $capacityUnitScaleUpLimit
After you expand the size of your SAN, you can either create more volumes or expand the size of an existing volume. You can't decrease the size of your volumes.
Update-AzElasticSanVolume -ResourceGroupName $resourceGroupName -ElasticSanName $sanName -VolumeGroupName $volumeGroupName -Name $volumeName -sizeGib $newVolumeSize
az elastic-san volume update -e $sanName -g $resourceGroupName -v $volumeGroupName -n $volumeName --size-gib $newVolumeSize
If you expanded the size of your SAN, see Create volumes to create a new volume with the extra capacity.