1GB RAID 5 Test Results

If you've got more than three HDD spindle to put in play, it makes sense to use one of the more advanced RAID configurations. RAID 5 is one of the most popular setups, primarily due to the balance it exhibits between capacity and redundancy. Not surprisingly, most NAS units that can support more than three HDDs also support RAID 5, so it makes sense to use it for test purposes. Most NAS products that can support RAID 5 go beyond the minimum number of drive bays, to a total of four, so that is the number of drives that I typically use to test with, even though I could get by with only three.

The results for RAID 5 read testing are very similar to single disk testing, which is not a bad thing. Given all the behind-the-scenes processing that goes on to calculate parity bits, these results show that most QNAP Turbo NAS units have the necessary power under the hood to keep the drives performing at their highest potential during read operations. When using RAID 5, the TS-419P II outperformed all of the other NAS systems and itself, in single-disk operation. It also edged past the TS-659 Pro II running in RAID 5. Read performance is clearly very strong with this system, which is a real bonus if you use it as frontline storage. Using it primarily as a backup system, you want top-notch write performance, which we'll test next.

The 1 GB RAID 5 disk write test shows the typical shortfall, when compared with the single disk results. It's well known that RAID 5 write performance can be a weak point, with all the computation overhead involved and the extra parity bits that need to be calculated and written to each of the drives. The only way to overcome that is with raw computational horsepower, which is what the TS-659 Pro II brings to the table. It's a shame that the simplest task any NAS can perform is basic backup duty, and in order to do that well, you need to buy the most powerful system to effectively reap the benefits of a multi-disk array. The reduced write performance with 1500 MTU is also a factor in RAID 5, so it's looking more and more like Jumbo Frames (9000 MTU) should be the preferred network setting for this unit.

Next up is 10 GB (1000 metric megabytes / 10,000,000,000 bytes) file transfer testing. Using the 4-disk RAD 5 configuration in each NAS, and a single Gigabit connection, network throughput will be put to the test, and the effect of any system or hardware caches will be minimized.

10GB RAID 5 Test Results

Looking at read tests with a single 10GB file, the TS-419P II hangs a little tighter in the groove, but can't quite keep up with its big brother, the TS-659 Pro II. The TS-659 Pro II improved its performance when transferring large files, which I thought was interesting. It shows how this unit is built to carry the heavier data loads. The TS-419P II gained some performance as well, but not as much as the TS-659 did. There was a small decrease in performance with Jumbo Frames enabled, which is counter to the Write results. It's not significant enough to outweigh the performance deficits seen in the Write testing, though.

Looking at write tests with a single 10GB file, the TS-419P II still suffers from the typical RAID 5 write penalties due to the computing overhead required to deal with the parity bits. The various caches built into the system help out on the smaller file transfers, but they get filled up and lose their effectiveness when dealing with large files like this. Even the TS-659 Pro II loses some performance when handling super large files. Once again, the 1500 MTU results lag far behind the Jumbo Frames performance, so it's a definite recommendation to set up the network interface with 9000 MTU, if you can. Of course, that will affect all your other Ethernet interfaces, so make sure all your other network devices are not negatively impacted by using Jumbo Frames.

All in all, my impression of the test results is that the QNAP TS-419P II puts in a solid performance, especially considering the added flexibility it offers in terms of advanced RAID support. I would feel better served by using it for front-line storage instead of a primary backup device, and that is consistent with the evolving computing infrastructure that surrounds us in our everyday lives. A device like this offers ones of the best ways of staying connected with your data, wherever you are. As for backups, I prefer off-site storage anyway.

Now, let's take a closer look at the internal workings of the NAS, where we can see the individual activity of the CPU, memory, and network interface. It's these support subsystems that have a big influence on the overall system performance, as I can easily demonstrate.

NAS Comparison Products

• QNAP TS-219P+ Gigabit 2-Bay SATA NAS server
• QNAP TS-259 Pro Gigabit 2-Bay SATA NAS server
• QNAP TS-659 Pro II Gigabit 6-Bay SATA NAS server
• QNAP TS-419P II Gigabit 4-bay SATA NAS Server

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