|Thecus N5550 NAS Network Storage Server|
|Reviews - Featured Reviews: Network|
|Written by Bruce Normann|
|Tuesday, 25 September 2012|
Page 11 of 15
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 Thecus N5550 has five bays, which could offer increased performance over a four-bay system, but we want to test comparable configurations here. Even the 8-bay QNAP TS-879U-RP is tested with the standard four disk contingent.
The results for RAID 5 Read testing show the Thecus N5550 running neck-and-neck with the more costly QNAP TS-879U-RP, racking up a 109.8 MB/s average read speed with 1 GB files. That's quite a feat, as the mighty TS-879U-RP uses its Intel Core i3 CPU to good advantage, and the Thecus does its thing with a Dual-Core Intel Atom. All of these NAS platforms do a credible job here, though. None of them would do a poor job in a typical READ scenario; it's typically the Write performance that separates the men from the not-so-men.
The 1 GB RAID 5 disk write test shows more clearly the strain that this particular RAID configuration puts on the NAS infrastructure. 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 why the ARM-based models lag behind both the Intel Atom and Core i3 units. The Thecus N5550 puts in a stellar second-place performance, reaching an average write speed of 111.5 MB/s compared to the 116.2 MB/s of the QNAP TS-879U-RP. That's a good jump up from the TS-659 Pro II which gets 97.4 MB/s out of the same four disks. The Marvell-based NAS devices just can't compete at the same level here. It's an inescapable fact that the simplest assignment any NAS can perform is basic backup duty, and in order to do that task well, you need to buy the most powerful system to effectively reap the benefits of a multi-disk array. Don't scrimp on the NAS platform if you can help it.
Next up is 10 GB (1000 metric megabytes / 10,000,000,000 bytes) file transfer testing. Using the 4-disk RAID 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 Thecus N5550 still hangs in there at the top of the performance ladder, with a read speed that's only 1.5% off from the highest performing unit. The results still favor the more expensive models, even though it's not a 1:1 ratio of improvement with higher cost. In order to do substantially better than this, you have to upgrade the network connection; GbE is only good for 125 MB/s, on a theoretical basis.
Looking at Write tests with a single 10GB file, the results are not all that different from the 1 GB tests. The Thecus N5550 runs at almost exactly the same average speed, in fact the Jumbo Frame results are identical. The same goes for the QNAP TS-879U-RP; the 9000 MTU write speed is the same, whether handling 1 GB files or 10 GB ones. The TS-879U-RP just laughs at the additional load of four hard drives; the CPU utilization never got above 25% during this test. The Thecus N5550 had to work a little harder, but the CPU load didn't get much higher than 50% during RAID 5 testing. The Marvell-based units always had the CPU maxed out in Write activity, and it really hurts the RAID performance.
All in all, my impression of these test results is that the Thecus N5550 is an excellent performer that exceeded my expectations. The marketing materials for this model have been a bit cagy about the CPU specifications, perhaps because Thecus thought people wouldn't believe the performance they achieved with an Atom Dual-Core. That's just speculation on my part, but the results surprised me quite a bit, especially Write performance. I'm a believer now, though.
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