Clones across SQL Server versions

Awen

Hi all,

we're are using SQL Clone (v3.1.0.15789) to spin up our DEV and TST environments from an image created from a PRD backup. Currently, everything is running SQL Server 2017. We are planning to migrate to SQL Server 2019, first DEV then TST then PRD, and I am concerned about how SQL Clone will behave in this case.

The short question is: if I create an image from a PRD backup running SQL Server 2017, will I still be able to create a clone on my DEV or TST environment running SQL Server 2019? Anything to pay extra attention to?

Thanks!
Awen

owen.hall

Hi Awen,

If you have an image made from a SQL Server 2017 database, and clone it into a SQL Server 2019 instance, the 2019 instance will upgrade the clone from 2017 to 2019 on attachment. (The underlying image won't be changed.) I would expect it to work fine, although the upgrade process might make the clone slightly larger than it otherwise would be, due to the changes being written into it.

You'd have more of a problem going the other way - trying to clone a 2019 image into a 2017 server. SQL Server will refuse to downgrade the database from 2019 to 2017, in that situation.

Hope that helps!

behibberd

Awen,

We have a similar upgrade scenario, and I actually set up some VMs and ran some tests to see how SQL Clone would behave between SQL Server 2017 and SQL Server 2019.  I can verify what Owen says.

In general, cloning a 2017 database onto a 2019 server instance works just fine.  Cloning a 2019 database onto a 2017 server instance fails.  The waters get a bit muddied if you change the version of the server instance used to generate the clone image.  Basically, you can't take a 2017 database, image it on a 2019 server instance, and clone it to a 2017 server instance.

I hope that all makes sense and helps in your decision making.  

Awen

Hi Behibberd,

thanks an lot for the word on the cloning instance version, that's a nice complement to Owen's answer and I definitely did not think about it! In my case I think we'll be fine (we consider the cloning instance as part of our PRD environment so its upgrade will be done after DEV and TST, and it will never be "in advance" compare to where we restore).