- When creating a new volume, start with the smallest drive first!
- When expanding capacity by swapping out drives, start with the smallest drive first!
Despite the publicized benefits and ease of management of SHR over classic RAID, a under-highlighted problem is that it still requires new drives to be equal to or greater than existing drives. So when creating a volume with mixed-capacity drives don't think you can just expand the volume in any order you want.
The SHR FAQ does mention this, however it's buried in a somewhat long-winded explanation (as opposed to the features it can provide which all start with a resounding "yes!"). It would be nice if the Synology RAID/SHR calculator would mention this to you as you played with drive combinations (it does mumble something in the footnotes about reading other docs though).2020-05-01