Hi loyal readers! I’m super excited today because the Azure SQL Database team have just announced two new tiering levels!
Basically, there announced a Basic and a Standard tier, in addition to the Premium tier. Ok, you might ask yourself why I didn’t mention the Web and Business tiers. Well, because they will be retired in 12 months :(.
The new tiers won’t just change the naming conventions. They come with some additional goodies too! First of all, there’s 99.95% SLA (as soon as they will be GA). Second, there’s self-restore, a service that allows automatic restoration of your database. Based on the tiering level, you can get your data from a restore point that was done up to 24h priorly, 7 days priorly or 35 days priorly (guess which tiering level offers restoration to any point within 35 days – you’re right: Premium). Moreover, there’s a disaster recovery scenario now too: basically, you can get up to 4 readable geo-replicas created for your database. And last but especially not least is performance. If before Premium, you complaint about performance was legit, starting now you are no longer allowed to compain about SQL Database performance :). In order to express Performance, the Azure team has defined DTU, the acronym for database throughput unit. Basically, a DTU combines CPU, memory, physical reads and transaction log writes into a single unit of processing. Based on this definition, “a performance level with 5 DTUs has five times more power than a performance level with 1 DTU”. (http://msdn.microsoft.com/en-US/library/azure/dn741336.aspx)
In other words, you have the option of scaling up your database in the most transparent way: if your database no longer keeps up with the high concurrency, just scale to a double, triple etc. powered system.
Moreover, there is ASDB, which stands for Azure SQL Database Benchmark. “ASDB measures the actual throughput of a performance level by using a mix of database operations which occur most frequently in online transaction processing (OLTP) workloads”. There more information on ASDB here: http://msdn.microsoft.com/en-US/library/azure/dn741327.aspx
When it comes to db performance, the most evident performance reference is the transaction rate. On the link provided before, there’s a table on each tier’s performance level; let me give you a hint on db performance today: you can get up to 730 transactions / seconds in your database, with 800 concurrent users. Wow!
If you plan to upgrade today, make sure that your subscription has the preview feature activated. If so, you’ll have to create a new server database and copy your existing Web/Business database over to the new server via any mechanism you want. The most comfortable one probably is exporting a .bacpac of your existing database and importing it to the new server. However, please keep in mind that this small drawback is only temporary: the team plans to offer you the option of scaling from Web and Business to Basic and Standard and vice-versa without moving the database to a new server soon (don’t exactly know when, but most likely before the new tiers are generally available).
Pricing will, of course, always be a huge question. If so far your pricing was GB based on the tier you’ve chosen, database size is no longer the only unit of measurement here, since performance will matter from now on too. Therefore, it still is extremely important to optimize your queries as much as possible and only leave the scaling as a last resort. However, if your pocket is wide enough, just go ahead and creat P3 Premium databases and surf around your query waves.