Migration of Synapse Data bricks activity runs from 'All purpose cluster' to 'New job cluster'

[IshaBudhiraja]

Could someone please help me with the below question:

1. How much time does the VM takes to deallocate the CPUs?
2. Can we check how much quota is required to run a script?

[Kaniz]

Hi @IshaBudhiraja, Let’s address your questions:

1. Deallocating VM CPUs: When you want to change the size of a virtual machine (VM) in Azure (either scaling it up or down), you might need to deallocate the VM first. Deallocating means releasing the lease on the underlying hardware, completely powering off the VM, and stopping any billing for compute costs. Here are the steps:

   • Deallocate VM in the Azure Portal:

     1. Open the Azure portal.
     2. Search for “Virtual machines” and select your VM.
     3. In the left menu, choose “Size.”
     4. Pick a new compatible size from the list.
     5. Select “Resize.” Note that if the VM is currently running, changing its size will cause it to restart.
     6. Deallocating the VM also releases any dynamic IP addresses assigned to it, but the OS and data disks are not affected.

   • Deallocate VM using Azure CLI: You can use the following command:

     az vm deallocate --resource-group <resource-group-name> --name <vm-name>
     

   Remember that deallocation is essential when the new VM size isn’t available on the same hardware cl...¹.

2. Checking Quota for VM CPUs: Azure enforces quotas for vCPUs (virtual CPUs) to prevent overuse. Here are some key points:

   • Total Regional vCPUs: This quota limits the total number of vCPUs you can deploy in a specific Azure region.
   • VM Family vCPUs: Each VM size family (e.g., D-series, E-series) has its own quota for vCPUs.
   • Overall VM Count Quota: There’s also a quota for the total number of virtual machines in the region.

   You can check your current quota usage using Azure CLI or PowerShell. For example, with Azure CLI:

   az vm list-usage --location "East US" --output table
   

   If you need additional cores, request a quota increase or delete VMs that are no longer needed².

Remember that while deallocated VMs don’t incur compute costs, storage costs (for disks) are indepen...³.

If you have any more questions, feel free to ask! 😊