Synology Expansion Unit (DX517) VS Standalone Synology NAS

Hi All! Whats the biggest difference between the expansion unit and just getting another Synology Standalone? Separate from price, is getting an expansion unit really worth it when the stand-alone units do so much more?

Thanks all!

So it depends heavily on what you are using it for, as their are pros and cons to each. The biggest differences are:

  • Expansion units mean you only have one box to manage - can make everything a ton easier to keep up with
  • The DX517 is connected via an eSATA port, which has a max throughput of 300MB/s combined, and that is before RAID overhead. (not a big deal if you are 1GbE anyway)
  • Having the expansion unit consolidates your RAM / CPU / networking. This lets you just upgrade in one place. It also can give a lower power draw, but Synologys are already so low power its not a huge savings.

Most people I have seen deploying them are businesses, where money for hardware is cheap, but maintenance is a huge pain

I owe you another lunch!

Yes I’m so afraid of losing my data so I don’t mind investing. I’m already so deep I might as well dive until the wallet breaks haha!

This is what I’m thinking (based on the 3-2-1)

  1. Main unit is the 1522+. That backs up too:

  2. The Expansion unit: which is either a hyper backup or clone of the main unit. And finally for offsite:

  3. Another remote Synology at my mothers house+ another cloud service as redundancy.

Bullet proof? Can the Expansion also be SHR-1 for redundancy there?

In this case, your backups on-sight should probably be a whole different synology, not an expansion unit.

There’s a few reasons why you want on-site backups, but one of those reasons is in case something with your synology starts to malfunction, you’ll have another Synology you can swap to until your primary gets fixed.

If it’s an expansion unit, you won’t have this luxury.

(also I didn’t realize they made an expansion unit for the 1522+, kinda cool)

Hi SynologyRichie. I have a DS720+ and DS923+. I like the idea of being able to just add to these units and increasing my Raid 2 storage pool incrementally. That’s my strategy. Rather than buying a DS1600 or 1800 series in the future, I can just add the expansion unit and then add drives (2 at a time) to expand my volume as needed. I’m a big Synology fan but when their HDDs cost 2X the cost of a comparable WD or Seagate drive and their RAM and their SSDs are also on the expensive side, and that their bigger NAS’s begin to require their super expensive enterprise drives to run, it makes sense to stick with a NAS that you can slowly expand and will work just fine with more affordable drives and memory.

I bought 2 x12TB Seagate Ironwolfs for $199 eaach. A 12TB Synology enterprise is closer to $400!! I can buy 2 Seagate or WD HDDs 5-6 years apart and they will probably last longer than 1 Synology HDD.