I added an extra drive to the original nas. ds3615 1.02 6.1.7. Made a raid group. made a volume. copied some files on it.
Put that drive in another pc with ds3617 1.03. Migrated that drive to 6.2.3. And did that again with another drive to see how it added to the first. Both worked fine.
So we now had my original nas config migrated and updated in the test pc. But without the drive that had all the packages on it.
Then I first put one of the test drives in the original pc to migrate. Then added an original drive. And only then the rest, with the volume the packages are installed on.
I guess thats the problem.
Normally you would probably migrate all your disks at the same time. Which makes it possible for all the packages to be able to access their files.
I guess if I would have just started with the drive with package volume, it would have also worked.
A lot of packages had to repair/recover or reinstall.
But after closer look, it was only the photo station that needed to be configured again. and indexed again.
Dockers configs for instance where still there.
It doesnt matter. I think filewise, this was the safest way to check if the files would still work after the update.
Even if no package at all would have worked. I rather have that than loose files