Azure App Services Launched

Today Microsoft launched Azure App Services, an exciting new umbrella platform for app developers that subsumes the existing Azure Websites (renamed Web Apps) and Azure Mobile Services (renamed Mobile Apps), as well as adding two more app services – Logic Apps and API Apps. The idea is to provide a much richer consolidated PaaS development experience that combines web applications, mobile back-ends and APIs with long-running workflows and tighter integration with external SaaS products.

All these new app types can now be hosted together under the same App Service Plan (previously a Web Hosting Plan) and share eachother’s data and features, for example Mobile Apps can now use Azure Web Jobs, a feature previously only available to Azure Websites. The end result will be better integration across all the web/mobile dev PaaS services and lower costs through the new shared hosting model, Websites and Mobile Services will no longer be billed separately.

The two new services, Logic Apps and API Apps are closely related. Logic Apps are managed, trigger-based workflows that integrate external web services using “connectors”, service adapters implemented using API Apps. API Apps are just regular REST APIs – like those built using ASP.NET Web API – except they’re discoverable via standard API metadata in a format called Swagger. This metadata describes services exposed by an API so its features can be discoverd and consumed by Logic App workflows or other apps. The API metadata also allows API client libraries to be generated automatically by Visual Studio, courtesy of the new Azure SDK.

Although some of the pieces that make up Azure App Services are still rough around the edges – the Logic Apps designer, for example, is very promising but still needs a lot of work – overall this is a fantastic evolution of the Azure dev platform that we can continue to use to deliver fantastic mobile and web apps to our customers. If you want to find out more, check out the four new vids from Azure Friday covering each of the new services.

Azure Operating System Disk Size Limit Raised to 1023 GB

A small but significant update from the Azure compute team today, the limit on OS disk sizes has been upped from 127 GB to 1023 GB, now taking advantage of the full allowed capacity of an Azure page blob. The old OS disk size constrint was there to deter users from running disk-intensive workloads on the OS volume, which already needs its allocated 500 IOPS (300 IOPS for Basic VMs) to keep systems running smoothly. However, that size restriction of 127 GB limited the size of OS disk we could migrate into Azure VMs, either manually or with tools like Microsoft Migration Accelerator, so this is another obstacle removed for shifting workloads into Azure IaaS.

When migrating or provisioning new workloads with demanding disk IO requirements, attach another data disk to get an additional 500 IOPS throughput. If that’s not enough, keep adding more disks and combine them into a single striped volume using Storage Spaces. Generally, the larger the VM the more disks can be attached, all the way up to the behemothic G5 which can have up to 64 VHDs attached with a potential 32,000 IOPS. And if even that’s not enough, turn to Premium Storage disks, persistent VHDs backed by SSD storage with up to 5,000 IOPS each. Stripe these into Storage Spaces you’re really off to the races.

One quick word however about using striped disks with geo-replicated storage accounts. Don’t do it, stick with LRS. If the primary region fails you probably won’t be able to restore from the secondary replica. The asynchronous write ordering to the striped disk set is unlikely to leave it intact after a failover.