elaborate on impact of SQL Azure VM size on import performance

Author: bawolfso

docs/migrate/migration-import-large-collections.md

@@ -45,7 +45,13 @@ Let's walk through how to accomplish this. At a high level, you'll:
 
 You can set up a SQL Azure VM from the Azure portal with just a few clicks. To learn how, see [Use the Azure portal to provision a Windows virtual machine with SQL Server](/azure/azure-sql/virtual-machines/windows/create-sql-vm-portal). 
 
-Azure DevOps Services is available in several [Azure regions](https://azure.microsoft.com/regions/services/) across the globe. 
+> [!NOTE] 
+> While setting up your SQL Azure VM, bear in mind that the performance of the VM and attached data disks will have a significant impact on the performance of the import. For this reason, we *highly* recommend:
+- Selecting a VM Size at the level of D8s_v5_* or above
+- Using managed disks
+- Consulting [Virtual machine and disk performance](https://learn.microsoft.com/en-us/azure/virtual-machines/disks-performance). Please ensure your infrastructure is configured so that neither the VM IOPS or storage IOPS become a bottleneck on the performance of the import. For example, ensuring the number of data disks attached to your VM is sufficient to support the IOPS from the VM.
+
+Azure DevOps Services is available in several Azure regions across the globe. These can be seen in the table below.
 
 > [!IMPORTANT]
 > To ensure that the import starts successfully, it's critical to place your data in the correct region. If you set up your SQL Azure VM in a location other than the regions listed in the following table, the import will fail to start.
@@ -71,9 +77,6 @@ Although Azure DevOps Services is available in multiple regions in the US, only
 > DACPAC customers should consult the region table in the ["Step 3: Upload the DACPAC file" section](migration-import.md#step-3-upload-the-dacpac-file). The preceding guidelines are for SQL Azure VMs only. 
 
 Here are a few more SQL Azure VM configurations that we recommend:
-
-- Use D Series VMs, because they're optimized for database operations.
-- Ensure that the D Series VMs have at least 28 gigabytes (GB) of RAM. For imports, we recommend Azure D12 V2 VM sizes.
 - [Configure the SQL temporary database](/sql/relational-databases/databases/move-system-databases#Examples) to use a drive other than drive C. Ideally the drive should have ample free space; at least equivalent to your database's [largest table](migration-import.md#step-2-generate-a-dacpac-file).
 - If your source database is still over 1 terabyte (TB) after you've [reduced its size](/azure/devops/server/upgrade/clean-up-data), you need to [attach additional 1-TB disks](/azure/virtual-machines/windows/attach-disk-portal) and combine them into a single partition to restore your database on the VM. 
 - If your collection databases are over 1 TB in size, consider using an SSD for both the temporary database and collection database. Also, consider using larger VMs with 16 virtual CPUs (vCPUs) and 128 GB of RAM.