Too late I found that the ShareSpace does not support these drives. After nights of struggling with this, I found a forum post below that confirms that is the case. Now, only the WD20EADS-type is supported. However, these are not for sale at the larger retailers here, only the WD20EARS-disks are.
This was in an attempt of upgrading the 4 TB ShareSpace to 8 TB.
Is there any hope that a future firmware update will support the WD20EARS-drives?
The ShareSpace has served me well since I bought it a few months ago, but with the Synology, I’ll be free to choose what harddisks to put in it. In a years time or so, I might replace the 2 TB disks with 3 TB ones.
Unfortunately, I cannot recommend the ShareSpace, due to the extreme limitations in upgrading/replacement of drives.