I'm planning to migrate an on-premises Windows file server to Azure Files using Azure Storage Mover. The server currently hosts one share containing roughly 60 departmental folders and about 1.5 TB of data, and the share is mapped on computers throughout the organization.
The goal is to retire the on-premises file server and have users access the files directly from Azure through their existing mapped drives. Since the storage cost difference is relatively small, I'm unsure whether Standard (HDD) or Premium (SSD) Azure Files would be the better choice.
We already have site-to-site VPN connectivity from our locations to Azure. Should access to the file share use a private endpoint, or is there a better network design? I'd also appreciate advice about DNS, VPN throughput, Azure File Sync, DFS, and any migration considerations I may be overlooking.
3 Answers
Before committing to Azure Files, consider whether SharePoint Online is a better fit for departmental documents. Separate sites or libraries can provide more natural department-level permissions, and users can still work with files through Windows Explorer using synchronization or a compatible mapped-drive tool. It may also have a more favorable cost model for document access than Azure Files, particularly when data egress is taken into account.
Azure Files makes more sense when you specifically need traditional SMB behavior, existing file-server permissions, or applications that require a network share.
Azure File Sync is worth evaluating, especially for branches with slower connections. A local Windows Server can act as a cache while Azure Files remains the central storage location. This can reduce repeated traffic over the VPN and may simplify the initial migration as well.
If most access will always travel over a WAN link, Premium may not provide much benefit because the network connection could become the bottleneck first.
A private endpoint paired with your existing VPN connections is a sensible design. Make sure DNS is handled properly: use a private DNS zone, and configure on-premises conditional forwarding to an Azure DNS Private Resolver or an appropriate DNS server in Azure.
The biggest practical concern is SMB performance over the VPN. Standard storage may be perfectly adequate if users mostly open smaller files occasionally, but heavy use, lots of concurrent users, or workloads involving many small files could expose latency and throughput limits. Premium will be faster, but you generally can’t switch an existing share from Standard to Premium in place—you’d need to provision the other tier and copy the data.
Putting the share behind a DFS namespace can also make a future backend change less disruptive to users.
That’s a valid alternative. The main reason I’m leaning toward Azure Files is to preserve the existing SMB-based workflow and avoid changing applications that expect a traditional file share.