Turn the cloud off at bedtime
When you operate in a public cloud such as Azure or AWS, you pay compute costs for all of the time that your instances are online. For your business facing and business critical systems, that is usually 24/7. But what about all those non production instances that run all night and all weekend? If these don’t need to be online 24/7, you can save up to 70% of your running costs by switching them off. This is what is meant by turn the cloud off at bedtime.
Example SQL Server VM
Your development hours are the standard 9am to 5pm. To allow some flexibility, you wish to make your development instances available to developers from 8am until 6pm.
| Weekly hours | Price | Saving % |
| 168 | £152.76 | – |
| 50 | 45.46 | 70.24% |
Deallocate is important
Ensure that your VM status is set to deallocated in the Azure portal to ensure you don’t receive ongoing billing for your compute expenses. This is best achieved by using the Azure Portal, CLI or PowerShell. If you just shutdown a machine, this won’t deallocate your compute resources and you will still be charged.
Compute savings only
The savings to be made are on compute resources as well as any associated licenses when they are included in your PAYG pricing. These are usually your biggest expenses anyway, but it’s worth noting that you will still be charged for any storage attached to your instance.
PAYG vs Reserved Instances
This post in primarily but not exclusively focussed on PAYG instances. There is a whole post to follow on reserved instances (RI) but I’d like to say this for now: You may still make savings by shutting down a reserved instance out of hours, if you have another instance (perhaps used by a dev team in a different time zone) that can pick up the free allocation. The billing for these is complex however. This page explains how RI reservations work against VMs in more detail.
How to turn the cloud off
When I first did this, it involved a mixture of Automation runbooks, PowerShell and instance tagging. There also wasn’t any flexibility to keep instance on for a bit longer without deleting the tag. Thankfully, Azure have made this process much easier now with this guide on how to start/stop VMs during off-hours.
What can’t be turned off
Certain PaaS services don’t allow the start and stop of services. Azure SQL Database and Managed Instance do not allow the stopping or pausing of the service. This takes this money saving option away from you. You could certainly save out of hours by scaling down your instance on a schedule using automation runbooks. This is a fairly quick operation for SQL DB. As for Managed Instance, it could take up to 4 hours so whilst this isn’t usually a great option for overnights, you could consider it for weekends.
The alternative is dropping and recreating your SQL DBs or managed instances each time using Infrastructure as Code. It’s more work but potentially worth the effort if you are running many and/or large PaaS instances.
What can be turned off
These posts are aimed at SQL professionals so I will stop short of listing everything on Azure however VMs as mentioned extensively in this post are the main choice. They are easy to stop and start manually, and the automation of this process is now easier than ever.
There is a PaaS Service that allows pausing of compute and that is Synapse Analytics. SQL Pools can be brought online for ETL purposes and paused the rest of the time. This can offer significant savings on Synapse Analytics.
Summary
Review all of your non production data services in Azure. If you have a lot, automation is the best and only way to keep fully on top of ensuring you are only paying for the services when you need them. Optimizing costs isn’t a one-time event. You need to be constantly on top of your bill to ensure that new instances are adhering to your cost optimization plans.
As always, please feel free to leave a comment if you wish to join the discussion.
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