The Challenge of Migrating to Azure SQL Database Managed Instance

When Azure SQL Database Managed Instance was introduced to the public at //build a couple of years ago, it was billed as a solution to ease the migration from either on-premises or even infrastructure as a service VMs. You would get all of the benefits of a managed service like built-in high availability and patching, automated backups, and you could do all of the things you couldn’t do in Azure SQL Database, like run CLR, use cross-database queries and have SQL Agent jobs without having to learn Azure Automation and PowerShell. The final big bonus was that you restore your backups from on-premises into the managed instance environment. No more dealing with DACPACs and crying, and drinking, and crying, and drinking, and crying.

 

photo of woodpile

Photo by João Vítor Heinrichs on Pexels.com

I had very early access to managed instance servers, and it seemed obvious to me that an easy migration approach would be to use log shipping. You could write your backups from your source server to URL, restore them with NORECOVERY to your managed instance, repeat the process with log backups, and voila you were in a managed instance. Quick and easy, and more importantly, if you were a DBA, nearly the exact same process you would have executed in your on-premises environment (except with backups to blob storage).

There was a long period of time, were we Data Platform MVPs were unable to deploy managed instances into our Microsoft subscriptions. Which is fine, when capacity is short, it should go to paying customers, not us idiots. However, this meant I was away from the product for a while. During this time Microsoft introduced the Data Migration Service, a comprehensive set of tools to move your data to and from a variety of platforms in an online and offline manor.

While DMS is pretty interesting tooling, I had mostly ignored it until recently. Functionally, the tool works pretty well. The problem is it requires a lot of privileges–you have to have someone who can create a service principal and you need to have the following ports open between your source machine and your managed instance:

  • 443
  • 53
  • 9354
  • 445
  • 12000

While the scope of those firewall rules is limited, in a larger enterprise, explaining why you need port 445 open to anything is going to be challenging. So in addition an AAD admin, the DBA is going to need a network admin to enable this. That service principal you created is also going to need the contributor permission on the entire subscription. Yes, that means it can create anything in the entire subscription. This is probably my biggest complaint. Microsoft does acknowledge this in docs, and says they are working to reduce the permissions that are required.

I’m currently engaged in a VM to Managed Instance migration, and when the client’s DBA was complaining about the complexity of the DMS, I suggested we just use log shipping like I had done when I first played with the Managed Instance service. I was trying to figure out how to automate the process, but then I figured I should just verify I could do a restore with NORECOVERY.

Msg 3032, Level 16, State 2, Line 11
One or more of the options (stats, norecovery, stats=) are not supported for this statement. Review the documentation for supported options.

Sad Trombone. That means the only way to migrate a database in near real-time is to use the DMS. And it’s going to take half of your IT staff in order to do it. In order to reduce the friction to migrations I’ve yelled at a couple of PMs about this, but I thought I would create a User Voice option.

https://feedback.azure.com/forums/908035-sql-server/suggestions/38267374-add-restore-with-norecovery-back-to-managed-instan

Please vote for it, if you are interested.

 

About jdanton1
A DBA, cyclist, cook (who likes to play chef occasionally)

2 Responses to The Challenge of Migrating to Azure SQL Database Managed Instance

  1. Pingback: Managed Instance Challenges – Curated SQL

  2. Golam Kabir says:

    you’re right – i then decided to go to aws

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