Whizzy-fast Microsoft Azure Premium Storage now available. With a catch, natch

Microsoft has announced general availability of Premium Storage for its Azure cloud computing platform.

Users of Azure VMs can now get speedier disk I/O thanks to the new service.

Premium Storage uses SSDs (Solid State Drives) and delivers up 32TB of storage with up to 64,000 IOPS (operations per second), according to executive veep Scott Guthrie.

Data resilience is ensured by three replicas held within the Azure region, and write operations are not confirmed until replication has taken place.

Geo-redundant resilience is more difficult, though you can snapshot a virtual drive to standard geo-redundant storage for disaster recovery.

Lack of fast storage is a common complaint from some Azure users, who will welcome today's announcement.

The purpose of the service is to support VMs with high-performance virtual disks, especially those managing databases. According to Azure CTO Mark Russinovich, using the service gets a 6x improvement in backup of a 2TB SQL Server database, and a 30x improvement in database restore.

Database write performance, claims Russinovich, is "2 times the write throughput on the same database running on an on-premise mid-level SAN".

There are limitations, though. Premium Storage is "currently supports only Azure Virtual Machine disks backed by page blobs", according to the docs.

It is not available for the other Azure storage types: Azure Block Blobs, Azure Files, Azure Tables or Azure Queues. Availability is currently limited to six Azure regions, including West Europe but not North Europe, though full roll-out is promised soon.

In order to use Premium Storage, you also need a DS series VM, a special variant of the Azure "Standard tier" VMs which has enhanced caching. Pricing is the same as for the standard D series. You cannot just attach premium storage to an existing non-DS VM.

Azure also offers a managed SQL Database service, which abstracts away the VMs and lets you pay by usage. Unfortunately the managed SQL service is slower than a well-specified VM option and has fewer features. SQL Server Reporting Services are not supported, for example.

This means that Azure users turn to running SQL Server on dedicated VMs to get full performance and features. Premium Storage increases the gap.

Despite the above limitations, Premium Storage is significant for Azure and enables high performance applications that otherwise could not be hosted there at all. ®