At the heart of the storage is a 6-core (12-stream) Intel Xeon E-2136 with a nominal frequency of 3.3 GHz, increasing at load up to 4.5 GHz. By default, the NAS has 16 GB of DDR4 ECC RAM (two modules of 8 GB each) expandable up to 64 GB.
Ask me, and I would prefer to see an AMD processor in a similar machine, because security problems in the architecture of Intel processors pop up on average once a quarter, and patches that close them lead to a significant drop in performance. And QNAP, unlike other NAS manufacturers, still not so vain there are several lines where AMD processors are used, in particular, Ryzen in models with the index TS-x77. Yes, who would have thought that the time would come, and we will consider the Intel server processor a disadvantage… But even among Intel processors, there are much more worthy candidates for a place in the NAS. For example, the recently updated Xeon D-1600 or Xeon D-2143IT series: these processors have built-in 10-Gigabit network controllers and more PCI Express lines, and in general, they were specifically created for NASes.
As for the layout of the QNAP TS-2483XU-RP, it is purely server: a high 4-unit body did not limit the imagination of developers, because they could realize any desire in the form of an expansion Board of full length and height. One such desire was to support RDMA (iSER), a direct memory access technology for Ethernet frame transfers. For iSER to work, its support is needed both on the storage and on the connected client or switch, and the best implementation of this chip is network cards manufactured by Mellanox. In QNAP TS-2483XU-RP the Mellanox ConnectX-4 Lx network card is installed, the powerful network controller with ASIC processor allowing to rank this Board to a class of “smart” network controllers SmartNIC, which are capable to carry out some functions on the analysis of network traffic without loading of CPU.
Returning to iSER, we can talk about such an advantage of this technology, as an increase of 40-60% of the speed of random access and a decrease in access time. Also, with intensive network traffic, the CPU load of the server decreases. The installed controller has 2 10GbE Ethernet slots of SFP + format, optional 25 and 40 Gigabit interfaces are available.
On the motherboard itself, you have four 1-Gigabit network ports, as well as six USB 3.1 (two Type-C and four Type-A). The network port configuration is optimal for using the device as a network gateway: optical Uplink for WAN and 4 copper interfaces for LAN.
As for USB 3.1, QNAP has a very interesting take on this interface: the company offers rack-mount expansion shelves that have their own RAID controller. Probably, permanent direct access to the data on these disk shelves is not intended, and it is planned to use them for backup or for archival data. In such disk shelves RAID-array configuration can be carried out through a common Web-interface, and jumpers on the body, at the same time, you can easily disconnect such a shelf from the storage and connect to a laptop, well, for example, if you are standing near the server cabinet, and you suddenly ran out of space on the laptop disk :). But in general so it is not accepted: serious storage represents one head device plus shelves of expansion which in turn-no more than SAS backplane in the steel case with the power supply unit. QNAP has also such expansion modules on 16 disks which you can connect to considered NAS already to 8 pieces sequentially, on 4 on each port of the SAS-adapter SAS-12G2E (it is got separately). To date, QNAP has 3 expansion modules with RAID controllers and USB 3.1 interface (TR-series): one 4-disk for rack installation and two desktop for 2 and 4 disks.
For SSD caching, a sign of good form is the installation of separate compartments, usually behind the storage case, and QNAP has such solutions in the corporate segment, but the TS-2483XU-RP is still a budget solution, and there are no separate compartments for solid-state drives here, so either donate one of the 3.5" compartments for SSD (the benefit of as many as 24 pieces), or install a special PCI-E Board for mSATA/M. 2 drives. And I must say that in the production of such boards QNAP succeeded like no other. They learned to produce combo boards that have a 10-Gigabit controller and 2 mSATA/M. 2 slots. Keep in mind that there are different adapters for mSATA and M2 drives: cards with index QM2-2S-for mSATA and QM2-2P - for PCI Express M. 2. Well, if you do not need a 10-Gigabit twisted pair network, then there is an option of such a Board without a network, including a 4-disk one. Please note-this controller has active cooling for the drives, and the fan status is monitored through the operating system of the storage, so it makes no sense to use non-original components here. In General, if you put aside fears about the unreliability of SSD drives, and do not think about the lack of hot swap, then these adapter cards are the best solution for NAS, which has 4 PCI Express slots empty.
For testing, we used Toshiba N300 hard drives designed specifically for NASes. In our testing, we used both helium HDDs with a volume of 14 TB, and conventional, “air” with a volume of 6 TB. In the presence of a good SSD cache to hard drives, as a rule, there is only one requirement: to work without breakdowns. According to Backblaze statistics, Toshiba hard drives have a failure rate of less than 1.5%, and although this is not a record, they are still worthy of working in the data Center.
To cache read / write operations, you must use a fail-safe RAID array of solid-state drives, at least-RAID level 1, that is, a mirror of two disks. Even if you have installed 2-3 QM2 adapters, you can combine the SSDS on these controllers into one common array. By the way, I do not get tired to repeat that besides traditional, simple and clear SSD-caching, QNAP still has a function of QTier, for automatic division of storage space into layers: slow for hard drives and fast for SAS HDD / PCI-e SSD. We have considered this technology in detail not only on the example of the corporate QNAP TDS-16489, but also on the desktop TVS-951 for digital studios . For those who are too lazy to read, we recall that QTier, unlike SSD cache, sums the volume of solid-state RAID array to disk, and transfers the most popular data blocks to the SSD on a schedule. Moreover, it may not necessarily be the whole file, but also some parts of iSCSI-LUN-s.