[1x Infiniband] Bought to expand my storage with hot spares. Very well built. Setup wasn't as easy as I hoped. Had to shut down and restart my NAS and then it picked up the DX517 right away. It is working very well though.

[1x Infiniband] I have been using Synology DS3617xs NAS Server for more than 3 years and wanted to expand the volume. Synology DX1215II is the most energy efficient and one of the most easiest expansion unit I have handled thus far. It's a simple plug and play; and you can manage the drives in any RAID configuration in the DSM.


Plus, I think it's the cheap 12 bay expansion unit i the market.


Also, works like a charm with any Seagate HDD - Exos, Ironwolf.

[1x Infiniband] Synology products have always been good to me. This expansion module did not disappoint. Great quality and worked flawlessly.

[28 lb] There's not a lot to say about the unit. Put disks in it, connect it to the NAS, power it on, and within a few minutes you've got lots more room for a new volume. It uses an InfiniBand link to the NAS, so performance is just as good as if the disks were directly connected. It also powers on and off in sync with the NAS. Good stuff!

[1x Infiniband] Rock Solid! East to Set up!

[1x Infiniband] Easy to install 5 new 16 TB Ironwolf drives into. I created a new volume and waited a couple days for it to format and do it’s Synology configuration.
This is a great way to expand your compatible Synology NAS. It is a little slower in R&W speeds than my main unit ( DX1621 ).
Future needs: I can always add one more DX517. But I doubt I will need to.

[Yes] I started with 4, 4TB drives in my Synology DS920+. I soon replaced those with larger drives. When that was no longer enough, I added the DX517 and bought one more 4TB drive, which added about 14TB to my total usable storage. It was a very fast and easy upgrade. I can also easily expand my storage even more by merely replacing those 4TB drives with larger ones.

I read a lot of reviews beforehand and for safety, ended up creating a second volume; so, each unit has its own. I had to move some folders around to make sense of it all but that too was fast and easy.

This was a very cost-effective way to expand my NAS and I am very pleased with the results.

[1x Infiniband] Had a 4 bay Synology that was almost full. This was an easy way to expand with 5 more bays. The supplied eSATA cable was long enough to reach the shelf below - the only wire you need between the two units (separate power cord to the expansion unit). Created a second storage volume with 5 new 12TB drives that added about 43TB. You want to make sure you do a second volume for the expansion, not extend your current volume. That way the 5 new disks are are not part of the original 4 disk RAID. Was very fast copying files over the eSATA cable from the old to the new volume.

Pricewise, this is cheaper than buying a new NAS and also saves you configuration time as far as setting up the system, users, etc.

This could also be a good way to backup a NAS. Copy everything to the expansion volume and then power down, unhook the eSATA cable, and take offsite.

[18 x 17 x 16.5"] Hopefully you are aware that this unit is an expansion, and does nothing on its own. I've had a DS3617xs for a couple of years now, and finally maxed it out, and this expansion unit has been working perfectly for me for a couple weeks now, giving me a total of 24 bays to work with. It provides power and cooling, and supports both 3.5 and 2.5 SATA drive bays out of the box. Also included are the drive caddies, screws for mounting 2.5 drives to the included caddies (3.5 drives fit without screws), the Synology cable that connects this unit up to the main unit, and the power cable (standard NEMA).


The only strange thing I've noticed is that drives installed in the main unit can be secure erased from within Synology's software, but drives mounted in the expansion unit cannot be. The software clearly explains this, but it was unexpected. Otherwise, I haven't found any limitations on the drives in this expansion unit.

[18 x 17 x 16.5"] Setup took less than 10 minutes. Nas recognized it without issue and had a new volume setup very quickly. Transfer speeds are great!