QNAP TS-451 Turbo NAS Server Review


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Closer Look: QNAP TS-451 Turbo NAS Server

The QNAP TS-451 looks like a lot of mid-sized NAS units in the market; four bays in a small tower format. It doesn’t look like a typical QNAP product though, because it’s finished in all white, instead of their signature black plastic and titanium livery. Four bays is the sweet spot for home office usage, because it allows you to use RAID 5 or RAID 6 and greatly decreases the risk of losing continuous access to your data. The four bays can theoretically hold 16TB of data, in JBOD or RAID 0 modes, with today’s state-of-the-art 4TB drives installed in each bay. That’s also a very risky option, which requires some sort of compensating storage strategy. Most users will choose the compromise method of RAID 5, which is still quite fast, given the right supporting infrastructure. A high performance storage solution with four drive spindles in play is always going to be better at most everything than a two bay device, assuming that both are based on reasonably modern technology. The greater flexibility for online RAID capacity expansion & online RAID level migration makes the additional cost of the extra drive bays looks like a bargain, instead of conspicuous consumption.

The TS-451 benefits from Intel’s constant CPU upgrades, particularly in the low-power sector that is commonly used in NAS products. The Intel Atom has been long overdue for a technology overhaul, and now that faster chips are available in the low power SOC format, QNAP wasted no time incorporating them into their product line. The TS-x51 series is meant to provide high performance on the high end of the home and SOHO series. There are 2, 4, 6, and 8 bay units available, in the same tower format. The size and weight of the TS-451 are typical for a device of this class: 177mm(H) x 180mm(W) x 235mm(D), and 6.6 pounds without drives installed. Each HDD you install will add about 1-1/2 pounds, depending on your choice of drive.  Most users will probably be looking at 2, 3, or 4TB drives for a NAS unit like this, and they’re heavier than most.


The TS-451 is aimed at home users, with or without a home office to support. Most businesses want continuous access to the data that enables their operations (AKA cash flow…), so a RAID configuration that includes some redundancy is undoubtedly called for. But, do home users need anything less? Perhaps yes, as I could argue that data security is more important for a home user than continuous access. That brings it down to the level of want, which I can’t discount. Multiple SATA 6Gb/s drives can be installed as: a single disk, RAID 0 (Disk Striping), RAID 1 (Disk Mirroring), RAID 5 (Block-level striping with distributed parity), RAID 6 (Block-level striping with double distributed parity), RAID 10 (AKA RAID 1+0, a stripe of mirrors), and JBOD (Linear Disk Volume).  RAID 5 has the option of a hot spare, which decreases MTTR but also decreases overall device capacity. RAID 6 offers some additional redundancy, allowing for continued operation even with two simultaneous drive failures, with no additional performance hit and only one additional drive.  This option is very popular because if one individual drive fails in a RAID 5 implementation, the array instantly starts operating like a RAID 0 configuration, which has NO redundancy. It stays in that vulnerable state until the array is rebuilt, which is a slow process that generally taxes the system to the max, and can take several hours to complete.   More than once, I’ve seen that situation go South; we lost the whole array and had to restore from tape backup, which meant lost work and a lot more downtime.

Each internal drive can only be formatted with EXT4, although external drives can use FAT, NTFS, EXT3, EXT4, or HFS+ file systems. HFS+ is a newish capability for QNAP, and those who recognize it will know that it serves as the primary file system for Apple’s OS X operating system. All Intel-based QNAP NAS units offer the additional option of AES 256-bit encryption and some of the larger units offer native CPU support for the recent AES-NI additions to the Intel64 instruction set. The Celeron J1800 Bay Trail-D CPU in the TS-451 does not have this capability, and data throughput takes a big hit when using full volume encryption. Performance with AES enabled is only about one third of what is possible without it. At least one vendor has implemented folder-based encryption, where you can limit the amount of data that gets encrypted to specific folders in the data structure.  If only a small portion of your data needs it, you can enjoy a balance of performance and security that isn’t available on the all-or-nothing units. Our tests on all QNAP NAS systems have utilized EXT4-formatted disks without encryption as the default option.


QNAP uses a newly-designed all-plastic tray to hold each drive on the TS-451, which reduces cost and weight for the model line. Each tray slides in with the HDD in the vertical position and locks firmly into place with the lever on the front.  Key locks are not included to secure the trays in place, which may or may not be a security requirement for you. The drive trays easily accommodate 2.5″ drives without any additional hardware; just use the correct mounting holes located on the bottom surface.  QNAP used to not recommend mixing 3.5″ and 2.5″ drives in the same enclosure, but the advent of SSD caching in their business-class devices put an end to that restriction. The trays are not labeled with the chassis slot number, which sounds like a small thing.  They are all physically identical and you can mix and match them all you want, until you build a drive array and then you had better remember which one goes where.  If you mix them up the NAS won’t recognize the array, and worst case you could end up destroying data as you try to figure out which drive is which. I always keep a stack of sticky notes around whenever I have to pull drive trays out of a NAS, just to be sure.


The chassis of the TS-451 follows standard NAS design practice and has just two major modules, the drive bay and the main controller board located along the left side. There is enough room at the top of the front panel for an LCD display, although the entire TS-x51 series does without one. The hard drive bays do not have LED indicators on them; HDD activity and status are displayed in a vertical string of LED indicators along the left side of the front panel. The overall NAS status and the status of the LAN and USB ports are indicated near the top of the panel. On the lower left, are the power button, a USB copy button, and a USB 3.0 port. A brand new feature that is starting to be included on new NAS model is the infrared (IR) receiver on the front panel. It’s hiding behind the dark circle just below the HDD4 indicator. With all the new multimedia features that come with the enhanced hardware and software, adding in the capability to use an IR remote control really makes those features more accessible. QNAP sells one as an accessory, called the RM-IR002.  It’s a fairly simple unit, with six buttons and a 4-way D-Pad for navigation.


There are only a few small ventilation holes on the bottom of the QNAP TS-451 Turbo NAS chassis. The main entry points for cool air are through the front of the drive trays and a strip of small holes on the left side panel. The air that comes directly in the front passes over the HDDs and is exhausted out the rear of the unit by the large 120mm fan. The air coming in the side cools off the rest of the components on the main controller board, where the Intel Celeron CPU is the only component with a heatsink. I usually don’t pay much attention to fan noise in the smaller NAS models, as it is never really noticeable during my daily use. The TS-451 also fits that scenario; noise was just not an issue, even though I had the unit on my desktop, quite near me. The 6-bay and 8-bay versions have twin fans to cool the additional drives, so they probably get a bit louder.


Looking at the back panel of the TS-451, you can see most of the hardwired I/O points, which are arrayed along the right hand side of the unit where the main controller board resides. (The unit is tilted over on its left side for this image.) Starting at the top is the small hole that guards the reset button from accidental actuation. Two levels of reset capability are provided, Basic System Reset (hold for 3 sec), and Advanced System Reset (hold for 10 sec). Next in line is a single, full-sized HDMI video port, which is an indicator of the new functionality that’s inside. Below that are two GbE ports, which are capable of being teamed into one virtual connection. There are no additional options available for network connections, as the TS-451 does not have an expansion slot on its controller board.  Below that are two USB 2.0 ports, in their normal black livery.  The next USB port is USB SuperSpeed (USB 3.0) spec, all dressed in bright blue.  Lastly, at the bottom is the pin & sleeve input for 12V DC power, which is fed from the 90W external power supply brick.


Now that we’ve had a thorough tour of the exterior, let’s do a tear-down and see what the insides look like. The next section covers Insider Details.


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  1. Piotr Z.

    If I’ve read the screenshot of ATTO correcty, you’ve just measured your C drive on SSD 🙂 1Gbit interface is exactly that – 1Gbit = theoretical 125MB/s. With the overhead it will max out on 110-180MB/s which you got in other softwares. I would suggest fixing that part of otherwise great review 😀

  2. Bruce

    Well, that might explain the very strange results I got….. Thank you so much for pointing that out. I will redo that test and post the true results.

  3. jamief

    QNAP suggest 3 possible usb tv tuners for use with this model….namely UPMOST DVB192A HD; Hauppauge Win TV Nova_T Stick (Device: 70019;HW rev DiF4) or Asus My Cinema U3100 Mini. I mistakenly bought a QNAP USB tv Stick when I originally acquired the above unit, thinking that it would naturally be compatible. Some of the above sticks are difficult to either isolate or acquire in UK and I was wondering if anyone else with similar NAS has had any luck with any other usb stick.

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