Microsoft has now announced its long pending Availability Zones in each region. It is currently on preview and recommended only for non-critical workload as Micorsoft does not provide any SLA now. With this, you can now provision your workload from different data centers in the same regions for resilience as you will have options to select between minimum of 3 AZs in each region with GA. However, it is now available only on East US2 and West Europe for Preview.
AWS currently operate 44 AZs across 16 Regions and 14 more AZs are already planned (44+14 =58). Microsoft currently operate in 36 regions and 6 more to come. If you assume that Microsoft will bring 3 AZs minimums at each of these regions, Microsoft would have (36+6) *3= 126 which itself is more than double the size of AZs across the globe. I agree, it does not make much sense to just play with the numbers so Microsoft need to bring the services that would help customers to make use availability zones and add value to their workloads hosted in Azure services. AWS currently offers multiple PaaS services for their Multi-AZ deployment model so Microsoft still need do good job on making sure that more services are available for Multiple AZ deployments.
Out of curiosity, I enabled AZ on my free subscription today. When you log into your portal, you get a pop up to enable AZ on your subscriptions and you can select the required subscription to enable it. It just took less than 30 minutes vs 1 hour mentioned in the MS announcement.
And then you get the message once it is completed. You can enable this per Subscription.
You are now good to go with creating VMs to those AZs available on those two regions. You can create only limited VM SKUs during the preview. Even though Microsoft document says you can create A2_v2, D2_v2 and DS2-v2, I was successful only with DS2-v2 and additionally DS1-v2. Once you select the right VM size, you get option to select which AZ to be used from the ‘Settings’. You cannot change the AZs once the VM is created, I could not find that option in the preview version.
Please remember that AZs are not for planning your Disaster Recovery (DR) because Data Centers may be close to each other or it might be possible to be in the same building, we still need to see if they are using separate buildings which are few miles away from each other’s. We do not know whether Microsoft will disclose any such information in the future release. In the real world, I have seen companies are using Data Centers which are few miles away for the DR even-though it is not recommended. AWS also does not provide any such information on proximity of their AZs . However, Microsoft says AZ will have independent power source, network, cooling etc. So, you need to make sure that you plan your high availability with these AZs but not your DR. I guess you may still need to pay for the intra-regional AZs data transfer but with reduced rate. Let’s hope Microsoft will announce much flexible feature when GA is available.
We have only limited details available from Microsoft on the AZs. So stay tuned for further updates from Microsoft.