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Performance

Computing performance is one of the most important parameters of a NAS but it shouldn’t be overemphasized. A modern NAS is a multifunctional device and it’s hard to simulate a real-life usage scenario in a lab. The 4-disk Synology NASes we are going to benchmark today are high-performance products, so we'll carry out additional tests besides single-user mode.

We’ll start out with Intel NASPT. As its templates are outdated already, the HD video scenarios were improved by increasing the size of test files to 8 GB (the total for each subtest). The File Copy to/from NAS templates were removed altogether.

We used Western Digital Red WD20EFRX drives for this test session. The NASes were connected directly to an Intel network adapter installed in an Intel Z77 based PC with an Intel Core i7-3770K and Windows 7 64-bit. We created a RAID (four disks in a JBOD, RAID0, RAID5 or RAID6) and a shared folder on the NAS and enabled Jumbo Frames (9K). The extra services were all turned off.

Working with the JBOD and RAID0 arrays which do not require extra computations, the DS413j delivers a peak speed of 80 and 100 MB/s for reading and writing, respectively. The speed of multithreaded reading doesn’t drop much with the RAID5 whereas the speed of writing lowers to 70 MB/s due to checksum calculations. This effect is even stronger with the RAID6. Well, that's the weakest hardware platform in this review and it's meant for home users in the first place. And home users don't usually run their NASes with RAID 5 or RAID6.

The dual-core DS413 can read and write at up to 120 MB/s unless it is a fault-tolerant array. Like with the previous model, the RAID5 is somewhat slower at reading and 40% slower at writing. The RAID6 is unexpectedly faster than the RAID5 in terms of writing.

We expected the x86 platform to be the best one among the three, but its behavior isn’t consistent. It is odd that the striped array isn’t the fastest one. It may be due to the disk controller and its drivers (the other two NASes have the same SATA chip). The RAID5 and RAID6 are good as they don't slow down much and deliver up to 100-120 MB/s at reading and writing.

The diagrams also allow you to compare the performance of each array type in each NAS.

As you can see, despite the different hardware configurations, the NASes aren’t much different in performance. All of them can use up a Gigabit Ethernet connection. However, a fast CPU is desirable for RAID5 and RAID6. Let’s try to find other types of applications where a fast CPU is called for.

One of them is the processing of photos and videos uploaded to the NAS. Photo Station and Video Station can index media files for a catalogue and also create optimized versions of files for easier viewing. For example, the NAS can make five previews for photographs with a frame width of 120, 320, 640, 800 and 1280 pixels.

There is an integrated transcoder to convert videos into FLV and MP4 formats (320 and 640 pixels wide, respectively) for watching on mobile devices and in web browsers, although this task would be more effectively performed on a PC. It is implemented in the DSAssistant utility which is used to upload photos and videos to the NAS. We checked this out, too, but you should note that there are other target formats on the PC and we selected the two closest ones. This test was carried out using 500 photographs with a resolution of 8 megapixels captured by a mobile phone and one AVI video clip (720x400, MPEG4, about 22 minutes long).

We don’t need much commenting here. If you plan to use your NAS for photo and video processing, the ARM platform isn’t a good choice. On the other hand, if you upload new photos in small batches and don’t hurry up to view them, even the junior NAS model can cope well enough. Besides, you can create previews on the PC. As for videos you intend to watch on mobile gadgets, it is best to upload compatible files or transcode them on the PC.

Here’s another additional test that may be interesting for MySQL users. The integrated MySQL server has a Perl-based benchmark in the standard distribution. First we used the phpMyAdmin module to create a database and a user. Then we launched the run-all-tests.pl script from the NAS’s console. The numbers show how much time it took the NASes to execute the script.

The DS413 is twice as fast as the ARM-based model and only half as fast as the Intel Atom platform. Considering that the latter is at the bottom of desktop CPU standings, it’s easy to find the relative position of the other platforms.

Although NASes usually consume less power than desktop PCs, the three products from Synology differ considerably in their power requirements. Unfortunately, our equipment isn’t very accurate at low levels of power consumption, yet we can see the difference between the NASes. Each of them supports two sleep modes: standard and deep. The Work scenario was emulated by running IOMeter with a 64KB template (100% writes, 100% random-address operations) on a block-access iSCSI volume created on a 4-disk RAID5.

The DS413 is the most economical in the deep sleep mode while the sleep and idle modes produce similar results with each NAS. Interestingly, the work mode requires the Intel Atom to consume much more power. The Atom CPU has a rich selection of its own power states, which must be why its power consumption grows so much under load. Comparing the different operating modes for the ARM and PPC platforms, we can estimate how much power is needed by the HDDs. It is about 15 watts in idle mode and 20 watts under load. That’s not much considering that we had four HDDs installed. The WD Red series seems to be optimal for NASes.

 
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