My adventures in swapping from xpenolgy to real synology (not that xpenology is not real)
Ran DS918+ at 6.2.3.xx with Hybrid(SHR) RAID on a j3455-itx mobo. I had 2x4TB 2.5" HDD effectively a RAID 1 configuration due to only 2 HDD.
I bought a DS720+ and took drive 1 from old system and plugged it into slot 1 of 720+. At this point the 720+ was bone stock (2GB of memory and no cache).
The system booted and straight up asked if I wanted to migrate from the 918+ at 6.2.3 to 7.0.1. Yep.
Once it is up it tells me degraded system due to bad HDD (the missing #2 HDD) I install a 14TB EXOS Seagate and let the rebuild begin.
Rebuild complete, power down and add 8GB of crucial memory and 2xNVMe 500Gb to cache slots and reboot. checkout system. Shutdown again.
Remove 4TB HDD and replace with another 14TB EXOS and rebuild again. I now have 2x14TB, still Hybrid(SHR)
Everything is working as expected. All packages are there, settings, everything.
Since that effort in early January I have added a DX517 plus another 14TB. At this point I can't add to that pool as I only have 1 drive protection but I have 4 more slots to build other pools etc. Quite happy so far but it is not an inexpensive process.
right now I still have 2 of the original HDD set aside for another experiment.
Good Luck
MF