NAS questions (volume size, RAM, cache)

my wife and me are both photographers, and we have hundred of thousand of multi megabyte image files (and as many few kilobytes XMP files, which sometimes may be modified at 40,000 in a single operation or, more often, 500 in a single operation).
Currently they are stored on a Synology DS213j with 2 6TB HDD inside and an 8TB WD Elements connected to one of the 2 USB 2.0 ports. Here we keep the older directory, connected via symbolic links. There is no redundancy.
The other USB port is connected via a switch to three docking stations where I put a set of 20TB backup HDDs, rotating sets periodically with a 3-2-1 scheme, and to an 8TB external HDD for out of camera RAW files backup.
The backup is managed by a .sh batch file controlled by the DSM Task Scheduler.
We access the data with three Win8.1 PCs on a cabled LAN.
Now the system is completely full, it’s low season and I don’t want to cram even more TBs in the poor old little thing, but to change it.
The current system of course is awfully slow when the USB 2.0 is concerned, and often has CPU overloads, mainly when hundreds of small XMP files are written at the same time. Occasionally the DSM decides to make thumbnails and index all the images and I spend hours to stop it and delete everything it did.

Now I would like to buy a new NAS for the same use. File server only; no media center, no streaming, no surveillance. Maybe access from WAN in the future, but I’m afraid of the maintenance. I’m a photographer, not a computer geek!
So I probably want a 4 or 5 bay NAS, possibly expandable. The backup works ok, but for a few issues that I hope to solve buying a multi slot docking station, and of course I’m looking forward to USB 3. I hope this will last until we both retire, in a few years.
I’m also intrigued by the 10GbE SFP+ port of the QNAP TS-431X, even if my PCs and switches would need an upgrade. The cables are all Cat6a with a maximum length of 7 meters.
So my personal Pros and Cons of Synology Vs QNAP:
– I am already familiar with DSM
– I like the eSATA port of DS918+
– I’m afraid of the Intel Celeron J3455 bug: I want my new NAS to last.
– The DS1515+ could override the CPU bug, but it’s far more expensive
– It gives me the impression that you get more performance for the money.
– three USB ports are more than two!
– I’m afraid to have to study a new OS.
– As already stated, I’m intrigued by the 10GbE port, but I don’t want to base the decision on an option that I will probably never call for.

My questions still unanswered:
– Should the DS918+ CPU die, would it be possible to change it?
– Is QTS Linux-based as well as DSM?
– How much RAM: 2GB, 4GB or 8GB?
– how do all the CPUs compare, and how much does it matter?
– how much a M.2 SSD would boost read/write speed performance?
– which is the maximum single volume size on the QNAP TS-431X?
– did I miss something crucial?


DS918+ and TS-453Be would be the best options. Once you mount them as network drives, then you don’t need to use NAS operating system anymore. With Synology, you can even automate data transfer to or from USB devices connected to a NAS. Bot Qnap and Synology are built on Linux backbone and can be accessed at a low level too.
The maximum volume for Qnap is

  • If the NAS has less than 4GB RAM, then the maximum capacity is 144TB.
  • If the NAS has at least 4GB RAM, then the maximum capacity is 250TB.

If Synology or Qnap CPU or motherboard dies, you can slide those drives in the replacement unit and get back to work.
The required RAM depends on how many apps you want to run. Most of the time 2-4GB is way enough.
The SSD boosts performance by around 20%. But in order to see the improvement, you would need to use 10GbE.

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