If you look through the scores of online forums where Network Attached Storage (NAS) systems are discussed, one of the most common user “wants” is for a NAS to simultaneously be a DAS (Direct Attached Storage). It’s a functionality that, at first blush, you might think easy to achieve but it turns out that it really isn’t because it’s not been an available option from any major NAS vendor.
I first discovered the market’s desire for a combined NAS and DAS when I was editing video and wondered if I could use the eSATA interface on the QNAP NAS I had in the Gibbs Universal Secret Underground Bunker. It turned out that, in common with other vendors’ implementations, the QNAP’s eSATA ports were host-only interfaces which meant they could only connect to a slave drive.
Then QNAP’s PR got in touch to tell me that QNAP had a solution for this problem; a NAS with a Thunderbolt 2 interface that provided a DAS service. The product is the QNAP TVS-871T which the company describes as:
… the world’s first Thunderbolt DAS/NAS/iSCSI SAN triple solution. With the incredible power of Thunderbolt 2 to double the speed potential to 20 Gbps, simultaneous 4K video transfer and display is enabled with considerable cost effectiveness.
Before we get to the DAS side of the TVS-871T, let’s do a quick spec check:
- Processor: Quad-core Intel® Core™ i7-4790S 3.2GHz (i5-4590S 3.0GHz is also available)
- Memory: 16 GB DDR3 RAM
- Disk drives: 8 hot-swappable 3.5"or 2.5”, SATA 6Gb/s, SATA 3Gb/s hard drives or SSDs
- Networking: 2 x 10 Gigabit Ethernet ports (10GBased-T) and 4 x 1 Gigabit Ethernet ports
- Thunderbolt: 2 x Thunderbolt 2 ports
- USB: 3 x USB 3.0 port ( front: 1, rear: 2), 2 x USB 2.0 port (rear)
- HDMI: 1 port
There are also two PCIe slots (1* PCIe Gen3 x8, 1* PCIe Gen2 x4) but these are occupied by the Thunderbolt 2 card and the 10GbE adapter.
That is, by any standards, a nicely spec’ed platform and fully loaded with eight 8TB drives you’ll get 64TB of raw storage and just under 56TB of usable storage if you select a RAID5 configuration. At the cost of one drive bay and less total storage, you can also improve system performance by adding an SSD configured as a front-end cache.
The TVS-871T, in common with all of the other models in the QNAP NAS portfolio, runs the company’s Linux-derived operating system, QTS (QNAP Turbo System), currently at version 4.2, which is well-designed with an excellent user interface along with being fast and robust.
NASs have become the Swiss Army Knives of network service and in common with other NAS vendors, QNAP has added functionality to their products with a range of home grown and third party applications and utilities. Where QNAP differs from other NAS vendors is in the range of add-on services and tools; along with the usual NAS features such as backup and multi-media services, QNAP offers their QEMU-based Virtualization Station for deploying virtual machines (which I described almost two years ago as “thoroughly and completely epically awesome”) and the recently released Container Station for deploying Docker and LXC containers (which I’m also raving about).
So, we come to the TVS-871T’s DAS functionality. In truth, this isn’t really DAS, it’s a dedicated point-to-point, high-speed Thunderbolt NAS connection but, that said, in practice, it’s just as good as if it actually were DAS given that eSATA delivers a data bandwidth of around 600 MB/s while Thunderbolt 2 is rated at 2.44 GB/s. This means you really can edit 4K video as if it were local with the added benefit of RAID ensuring your masterpiece doesn’t vanish in a cloud of bits after your drive bites the big one is not to be underestimated.
The way that the Thunderbolt service works in this scenario is that when first connected or reconnected to computer running either Windows or OS X (all of my testing was using an iMac 5K running OS X 10.11.4 “El Capitan”) an IP connection is established either with the NAS having a static IP address or it gets a dynamic IP address from the computer which acts as a DHCP server. That’s it, the Mac and the NAS are now linked and in the OS X Finder you can select which file service to use (AFP is somewhat faster then CIFS in this setup). Much the same process applies for Windows configurations. Supported protocols include:
- AFP (Apple Filing Protocol)
- NFS (Network File System)
- SMB/CIFS (Microsoft File Sharing)
- File Transfer Protocol (FTP)
You can configure drive mappings using QNAP’s QFinder Pro utility or just navigate the network connections via the OS X Finder or Windows support. I’ve seen some occasional initial Thunderbolt connection problems when the TVS-871T is configured to use a dynamic IP address which, I suspect, was due to the OS X Thunderbolt DHCP service not being ready quick enough and, as a consequence, the TVS-871T timing out (you can’t restart the Thunderbolt service without a complete restart of the TVS-871T).
My only complaint about QNAP’s products is that their documentation is a little weak. While the sheer scope of their product offerings obviously makes it tricky to keep the huge amount of documentation up to date it can still be laborious to find answers even though the community forums are a great resource. Also, while it's not QNAP's fault, when it comes to third party applications, the documentation varies wildly in quality which can be frustrating when you find a NAS-based app you really like and then run into problems. Again, the community forums are your friend.
You might be wondering why the TVS-871T has two Thunderbolt ports: Sure, two separate computers can each have their own dedicated Thunderbolt connections to a single TVS-871T but you could also daisy-chain up to six more TVS-871Ts or up to six NAS expansion enclosures (TX-500P or TX-800P) expansion storage units.
The bottom line is that if you’re looking for combo NAS and DAS (along with iSCSI SAN support), the TVS-871T is it! Great features, great performance, and priced at around $2,800 without drives, the TVS-871T gets a Gearhead rating of 5 out of 5.
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