Issue in "Upgrade Prerequisites" We should clearly state that default btrfs scheme partition is not supported

[mlaguilharre]

Upgrade Prerequisites:

https://documentation.suse.com/suse-distribution-migration-system/15/html/distribution-migration-system/index.html#id-upgrade-prerequisites
It seems obvious and it is stated in TID https://www.suse.com/support/kb/doc/?id=000021483 that our default installation scheme is not supported for SUSE Distribution Migration System. However the vast majority of our customer who lift and shift workload in the cloud will not be able to migrate.
This should be emphasized in our documentation and not only in a TID.

[schaefi]

Actually the referenced support ticket is pointing to the issue if system partitions like /usr, /var are spanned across multiple devices the DMS will not be able to upgrade them because in the offline live system environment only the root disk gets attached and other devices will not be visible in the upgrade live system.

So this is not related to btrfs or LVM. We have documented this caveat here:

https://documentation.suse.com/suse-distribution-migration-system/15/html/distribution-migration-system/index.html#id-caveats-and-unsupported-conditions

In systems that contain multiple root file systems on different mount points only the root file system mounted on / (primary system) will be migrated.

I agree with you that this part of the documentation should be more detailed

[schaefi]

In addition I would also like to mention that an online upgrade process is also available as unoficial method to migrate basically everything.

• https://github.com/SUSE/suse-migration-services/blob/master/README_QA.rst

[Optional] Testing in online upgrade mode (not officially supported by SUSE):

I have not mentioned it in the docs because SUSE does not support it, but it works better than the offline process ;)

If PM would make a decision to allow online upgrade via DMS we would have an opportunity to migrate from the running system which eliminates the device issue you see

[schaefi]

Regarding the doc enhancement I will take a look when there is a free cycle