Extending SHR storage pool over to a DX517 expansion unit risky?

[Enquiries]

At my home there is a DS920+ with an expansion unit. I am really satisfied with the DS920+, but i need some more storage. I have 4 slots open on the expansion unit, one slot is taken up by a single disk that serves the synology surveillance setup. I would like to expand the original pool over to the expansion unit and just add a few harddisks there, but online i can find conflicting information about how risky that would be if either the NAS or the expansion unit would stop funcioning. Would the whole pool be corrupted and unrecoverable? Or would i just be able to replace the expansion unit and continue as before?
I could ofcourse just set up a new storage volume just with disks that are located on the dx517, but that seems like a waste of space becouse of the extra redundant HDD i would need for that. I've heard you mention this quickly in one of your video's, but i cant find any deeper dive into this topic anywhere on the internet.

Thank you!

[ed]

Synology's expansion units are designed to seamlessly extend storage capacity, and the risk of data loss during such expansions is minimal. The SHR (Synology Hybrid RAID) technology provides a level of flexibility and redundancy that ensures your data's safety. In the rare event of a failure, your data remains intact on the functioning drives. Replacing the faulty unit or NAS is a straightforward process, and your storage pool should be recoverable without compromising your data. Synology's reputation as a market leader underscores the reliability of their products. Feel confident in expanding your storage pool using the DX517, and in case you need more insights into your specific setup, you can explore the Synology community forums or reach out to their support.