SQL Developer edtion as a new node within an Enterprise Availability Group

Question

We currently have a 2 node Availability Group in our test environment running SQL Server 2017 Enterprise Edition.

I need to downgrade these both to Developer edition, since we are not using this in a production environment, and the use of licenses for Enterprise Edition is cost-prohibitive.

My initial plan is:

1. Uninstall the secondary node, install Developer 2017
2. Sync over jobs, logins, etc via DbaTools PS library
3. Add the newly built Developer instance to the existing AG on the primary node
4. Failover and test in Developer instance. If all is well, repeat on old primary node.

My initial feeling is that this "should" work given that Developer Edition has all the features Enterprise Edition has. The pessimist in me feels that Microsoft will definitely not let me do this and how would you match the patch levels for a different version!?!

Has anyone had experience with this before or know if it's possible?

My fall back is to migrate the databases manually into the newly built instance on the passive via backup/restore, eventually creating a new AG to finish the project off.

Answer 1

The requirements for SQL Server Availability Groups say:

Each server instance must be running the same version of SQL Server to participate in an availability group.

Here, "version" means the instance version, so SQL Server 2017 in your case. You should ensure all instances are running the same Cumulative Updates and security patches, as well. This doesn't mean the same Edition of SQL Server.

You should be able to remove the secondary node from the existing AG, downgrade the instance to Developer Edition via the normal route, install Developer Edition, and join it to the Availability Group without issue. You'd then make the secondary into the primary, and repeat the process on the original primary. If you have a hypervisor host handy, I would recommend creating new server VMs instead, with Developer Edition installed, and using a Distributed Availability Group to transfer the databases over to them.

Answer 2

how would you match the patch levels for a different version!?!

Here is my plan

• apply latest CU
• shutdown SQL instance, save master, model, msdb data and log files
• uninstall SQL Enterprise edition
• install SQL Developer edition.
• patch it to the same patch level as from step 1
• shutdown SQL Developer edition. Overwrite master, mdsb and model data and log files from the ones in step 2
• Start SQL Developer edition
• done. No need to sync jobs, logins, databases

Has anyone had experience with this before or know if it's possible?

Yes, I did it based on

https://www.sqlskills.com/blogs/jonathan/downgrading-sql-server-editions/