The photos showing the disc with the tone arm (without cover) are for illustration purposes only. Hard drives are always protected. They would be too vulnerable without it.
It already works with a DS920+.
The Digitec specification list says it is the ST4000VN008 model. As it also says in the Synology list. The part you mentioned after the name is not actually mentioned by any dealer.
Only hard drives that have been tested and are therefore officially "recommended" by Synology appear in the Synology list. If a hard drive is not listed, it does not mean that it does not work with one of their NAS.
You can always wait, after all, everything always gets cheaper.
I bought WD Red Plus because I think the price is reasonable, the HDDs won't get any cheaper in the next few weeks.
Hi, this should not be a problem, as the connection of the hard drives is backwards compatible. Unfortunately, however, the performance will not correspond to that stated in the specifications, as the connection limits some things here.
To be sure, you can check the compatibility list at either Synology or Seagate.
Simply select your NAS model and the compatible hard drives will be displayed. Inserted at the bottom left:
https://www.synology.com/de-de/compatibility
https://www.seagate.com/de/de/internal-hard-drives/hdd/ironwolf/#compatibility
Of course it will work. Any SATA disk can be used, it doesn't have to be the same brand or model. You can even insert a larger capacity disk, if the two are mirrored they will sync up to the original 4TB capacity, and once you replace the second with the same larger capacity, the Synology will automatically adjust the maximum storage capacity to match the installed capacity.
If the external enclosure supplies enough power, I don't see a problem. I rather treated myself to the Synology C2 cloud storage. Then created a job in HyperBackup and now live worry-free. The backup is encrypted locally and then uploaded to the C2 Cloud.
You need a DS216+ or DS216+II or higher, the DS216j doesn't recognise the disk, maybe a fireware update will help, but better check with Synology first.
Notes
The hard drive is recognised as compatible according to the manufacturer, as others in the series have passed the compatibility test.
https://www.synology.com/de-de/compatibility?search_by=products&category=hdds&p=1&product_bays=1&product_name=DS115j&filter_size=4TB¬_recommend_mode=false