Synology DX517 NAS Expansion Unit - Review

DarqueKnightDarqueKnight Posts: 6,656
edited February 25 in Going Digital

My Synology DS918+ NAS was set up in February of 2018 with four 8 TB Western Digital Red drives. My video collection took up 17 TB (55%) of the available 30.7 TB of storage. I assumed the 13.7 TB of free space would last a long time (years) since I only buy a few titles per year. At the time of initial installation, my video collection was 71% DVDs, 29% Blu-rays, and 0% 4K Blu-rays.

In two year's time, the format distribution of my video collection had changed to 44% DVDs, 51% Blu-rays, and 5% 4K Blu-rays. This redistribution was due largely to replacing DVD titles with their Blu-ray versions and replacing Blu-ray titles with their 4K Blu-ray versions, rather than acquisitions of new releases. Over the past two years, many of my favorite DVD titles have been re-released in Blu-ray format with high quality remastering and some of my favorite Blu-ray titles have been re-released in 4K format.

Figure 1. Synology DS919+ NAS and its TeraDak DC-200VA linear power supply.

In two years time, the NAS's 45% storage vacancy had dwindled to 19%. I thought it would be wise to proactively increase storage space. My first thought was to replace the DS918+ with a Synology eight-bay DS1819+ equipped with 10 TB Western Digital Red drives.

Figure 2. Synology DS1819+ NAS.

After some research, I decided to add a Synology five-bay DX517 expansion unit to the DS918+. This solution was less than half the cost of the DS1819+ and its associated accessories (additional RAM, backup drives, etc). It was also less than half the setup time. Plus, I now have nine bays compared to the DS1819+'s eight. In the future, when I am more dedicated to video than I am now, I might invest in a larger, faster NAS like the DS1819+.

Moving to four larger drives was considered, but I am rather fond of less complex mechanical devices. WD's Red drives come in capacities up to 14 TB, with commensurately smaller and more complex inner mechanisms, and, of course, commensurately higher price. I have more confidence in an 8 TB drive with 4 platters than in a 14 TB 3.5" drive crammed with however many platters are required in order to reach the nominal storage capacity. My preference is having my video collection distributed among a larger number of smaller drives than a small number of large drives.

Figure 3. Synology DS918+ NAS (left) and DX517 expansion unit. The DX517 attaches to the DS918+ via an eSATA cable.

I am currently using only two of the DX517's five bays, for a total storage of 46 TB across six 8 TB drives, and a total occupancy of 25 TB (54%). Each 8 TB drive has 7.676 TB storage available. The NAS's operating system reserves 0.324 TB of space on each drive. Filling the remaining three bays with 8 TB drives would provide 69 TB total storage with a currant occupancy rate of 36%.

I have not noticed any speed or performance differences when loading files into the expansion unit or when streaming video from the expansion unit.

Unlike the DS918+ NAS, the DX517 did not come with an electrically noisy switch mode power supply. It came with an 18 AWG IEC power cord, which I quickly switched for a Signal Cable 12 AWG Digital Reference power cord. The DX517 was plugged into one of the available outlets on my PS Audio P5 AC regenerator.

Figure 4. The DX517's stock power cord is inside the coiled Signal Cable Digital reference. I would have preferred to use a larger (10 AWG) Signal Cable MagicPower cord (top). However, the DX517's IEC inlet is recessed over an inch into its back panel and the MagicPower cord's plug was too big to fit.

Figure 5. I am still fascinated by the fact that my entire video collection can fit in a little box, and that all content is streamable to any computing device in my home.


Digitizing my movie collection:

Ripping All DVDs and Blu-rays to NAS:

TeraDak Linear Power Supplies For Synology NAS Units:

Living The Disc-less Life:
"So hot it burns Mice!"~DK
"Polk SDA-SRSs are hopelessly out of date both sonically and technologically... I see no value whatsoever in older SDA speakers."~Audio Asylum Member
"Knowledge, without understanding, is a path to failure."~DK
"Those who irrationally rail against something or someone that is no threat to them, actually desire (or desire to be like) the thing or person they are railing against."~DK


Sign In or Register to comment.

Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!