Synology 5bay Expansion Unit DX513 (Diskless),Black

I got this as an expansion to my DS716+, and it's been working great.It is a little on the pricy side for a device that only work as a slave, and the fact that it connects to the main unit solely with an eSATA cable has led many (including, initially, myself) to a misunderstanding that device is just a box with a power supply, but it's worth pointing out that there's considerable logic inside. It has its own data control backplane that works independently of the main unit, and allows each disk inside to be individually addressed or built into volumes, queried for diagnostic status or temperature, and perform any of the functions of a locally attached disk. The main NAS unit also has full control of the expansion unit's fan speed, power state, LEDs and power button function, so it really is just a good as flexible as having a NAS with more drive slots.The build quality is just as solid as my DS716+, and the dimensions match up so they look natural sitting next to one another - the DX513 is noticeably deeper, however, and the side bezels are a little thicker.It has an internal power supply that connects with a standard and included IEC three prong cable( which differentiates it from the 716+, which comes with an external switching-type "brick") - this is a nice feature that creates less clutter and alleviates some of my fear of accidentally disconnecting it.It uses the same toolless, screwless drive sleds as the DS716+. Mounting laptop-profile drives requires screws, and it comes with all the screws that you'd need to put laptop drives in all fives bays at once (if that were for some reason a thing you actually wanted to do), but most people shouldn't need to touch a screwdriver in the setup.It's also impressively quiet, and I'm comfortable having it set up in my bedroom without it being a distraction - I've been running it for months and the fans have never spun above a low, almost inaudible level.Altogether, if you already have a Synology NAS and you want more drive bays, I'd highly recommend it. If you're planning to buy a Synology NAS for the first time, it would be feature equivalent but more cost effective to buy a unit that already has the capacity you need.

I used to run a Windows Home Server setup, and this is MUCH easier to work with and add drives to - especially after Microsoft removed the Drive Extender feature in WHS 2011. I highly recommend Synology devices to all my friends - and even if this unit is out of your price range, there are lower cost units that don't hold as many drives that perform just as well.I'd say the only possible downside (if you would even call it that) is the amount of time it takes the unit to ingest additional drives. I have 12 drives in the unit currently (Using the DX513 expansion module as well) and it takes about 24 hours to add an additional 3TB drive. BUT, this is a ONE TIME ordeal and the system is accessible and usable the entire time. Other reviewers have mentioned the long delay, but they aren't understanding what the system is doing - It's formatting it, then running a consistency test/testing the drive for errors, and then migrating+balancing data from all the other drives across the new array.Overall, I can't say enough good things about this unit. - I would HIGHLY recommend pairing this system with the WD Red NAS drives - they cost a little bit more, but the 3TB version can usually be had for $140-160 and they are worth every penny.

this is a great unit, I have been running it with one of the expansion bays for nearly three years. It did give me a few scares at times when it stops working and would not turn on. Then i realised that it was getting too hot and I had to create proper ventilation for it, now it works like a charm. I will be looking to upgrade once the new Intel processors are out.

I have been using Synology equipment since 2014. I have gone through many bugs, deficiencies, enhancements and software updates during that time. As with any hardware platform driven by software there is inevitably these kind of challenges but what I didn't expect was to be forced to throw away equipment in less than 4 years due to Synology's approach to hardware repair. If you encounter a hardware issue with Synology hardware after the warranty period you will have no way of getting it repaired by this company and will have to throw it away!I made this inquiry to Synology:"Hi do you have a repair service for this unit? Unfortunately it is just outside the warranty period. I hate to spend another $500 to replace this unit if there is a more economical approach. What are my options?Here is a direct quote: "Unfortunately we do not offer repair services for any of the devices. For some clarification regarding repairs, we unfortunately aren't equipped or staffed at this time to do repairs. Any hardware refurbishment is handled at our headquarters in Taiwan, so there would already be significant delays just from shipping back and forth, on top of that would be the shipping costs."So now I have to spend another $500 to purchase a new unit. I have to install 5 new enterprise hard drives and build a new raid volume. This by the way takes days!I now have a bunch of Synology equipment that will need to be thrown away as it fails. I have many thousands of dollars invested in this equipment but even more importantly I have years of investment in this platform. So the lesson I have learned is to go only with a company who stands behind their hardware not just through the warranty period but beyond. In the end analysis I might have just replaced the unit if the repair was going to be too expensive but if it was something simple I would have opted to repair the unit.