Fast five-drive NAS box fills more storage gaps

THE CORE FUNCTIONALITY is obviously NAS, but the N5200 does a lot more. It will share to just about anything under the sun, and it would be remiss if we didn't mention web sharing. The N5200 has a built in web server that you can drag and drop files to. Again, if you set up the users, groups and ACLs, you are done. Same with FTP, there is no more setup to do, just hit the N5200's IP with a browser. If you want a little more security, I would recommend turning off all non-secure web access, SSL is a good thing.

Once you have your NAS up and running with terabytes of your valuable data on it, how do you back it up? There are two options, Snapshot and Nsync. Snapshot does just what it says, it makes a snapshot of the entire system, either on a schedule or once.

Nsync luckily has nothing to do with the band, it syncs parts of the system to a remote FTP server or other Thecus box. You simply give it a remote server, password, and schedule. It then fires off the files when you need it to. Again, both backup options are really simple.

All the features in the world do not do very much for you if it doesn't perform, and happily the N5200 does. I retested the N4100 and then went on to the N5200 with the same drives, five Western Digital Caviar RE2 drives, model WD5000YS to be specific.

A quick word about these drives, they are fast, quiet and cool. If you look at the numbers on Storage Review's roundup of 500GB drives, the WD5000 came out rather well. My experience with them in both NAS boxes showed they were virtually silent, you cold not hear them from my test station eight or so feet away over the noise in the room.

Even after heavy use, the hottest they got was slightly warm. I don't know if this was a case of the N5200 having a the back dominated by a fan or the drives being very cool on their own. It is probably a little of each.

The RE2 line is made for RAID operation and offers lower levels of vibration and high MBTFs. While I didn't test it objectively, the box and drives operated quietly and unobtrusively. There were times that the only reason you knew it was on was because the LCD backlight lit up the room when you turned off the lights to leave.

So, how well did it work doing the job it was designed to, sending files hither and yon? I tested the N5200 with a Conroe 2.93GHz with a WD Raptor 74GB, 2GB of Kingston DDR2/800LL memory on an Intel Badaxe board. It was running XP with all the latest patches and no antivirus/antispyware in the background. All the networking was done over a Linksys EG008W 8 port GigE switch. I didn't set it to full duplex because I have yet to run into a box in the real world that has it turned on.

All testing was timed manually and repeated at least three times. It rarely varied by more than 1%, and if it did, the testing was rerun, and the median value was chosen for the result. All of the files were mostly incompressible media files, with the large ones being over 500MB each and the small being about 5MB.

To answer the question of how fast, the short story is it can sustain 25+ MB/S until you get bored. The N5200 simply blows it's older brethren out of the water, 4-5 times faster in most cases. While there data is good, it is not always consistent.

Obviously RAID 0 is faster than RAID 5, there are no checksums to compute, and there is an extra spindle to push 25% more real world data out onto the wire. The numbers reflect this with an approximately 10% consistent speed advantage for RAID 0 in our testing. This is completely expected.

Also expected is that large file transfers were faster than smaller ones, and that is indeed the case. For writing to the N5200, there is about a 1MB/S speed difference between writing the large files and the small, and it remained fairly consistent. This tells me that the N5200 is quite efficient at it's caching, it can use those 256MB to batch up files and write them at once.

The only odd spot, and it is quite glaring, is the reading of small files, it is about half the speed of reads. This flies in the face of any obvious explanation I have, normally with RAID 5 you expect writes to be slower than reads. RAID 5 has to do a RMW (Read/Modify/Write) where it reads a block, computes a new checksum, then writes it back. This hammers performance on RAID 5 but does not occur on RAID 0. This performance hit occurs only on read, and it also happens on RAID 0 so that is not the cause here.

The best explanation we can come up with here is the aforementioned caching. With many versions of RAID controllers, you have to have all the drives heads able to read the data before you can transfer the first byte. This means that the slowest head seek will be the outer bound for speed. Additionally, if the rotational latency is on average half a spindle rotation, 1 second / 7200RPM * .5, and in this case, you now have five chances to get it wrong, and on top of that, the slowest drive may not start looking until the other four are done. It is a worst case coupled with another worst case.

So, theoretically you get the worst possible track seeking time coupled with the worst possible rotational latency. If you consider you can batch up writes in RAM to minimize this, and on top of that, writes are essentially sequential from track to track, you can see why writes are faster. That said, the gap here is so large I suspect there may be a few others factors at play.

I would expect the gap to narrow a lot on a heavily fragmented drive or with many users banging on the N5200. This one puzzled me a lot, and if anyone can give me a good way to narrow down the reasons, please drop me a line.

Overall, performance was very solid. You could probably bump things up a notch by turning Jumbo Frames on the network and setting duplex to full in both cases, but I don't really consider that to be a real world scenario, especially in the markets the N5200 is targeted at.

CPU use, the major gripe in the N4100, is now simply not a problem. The worst case scenario, reading and writing lots of small files showed there is room to spare now. On writes, the CPU was in the 50-75% usage range, and hovered in the 30s for reads. This was measured through the HTML management window, so it is likely we missed spikes, but it was consistent and repeatable. In most cases, the CPU was puttering around in the 0-5% range.

There are a few other features worth mentioning, printer and USB support. The N5200 will put a printer on the network and expose it to the world. Plug it in, map it and print, not much more to say. It is a handy feature to have, and it adds nothing to the cost.

There are also three USB features worth noting. First is you can put in an 802.11b/g dongle to make the N5200 wireless. Since you would be dropping the speed considerably, I am not sure this makes much sense unless you don't already have a wireless infrastructure in place.

The other two are USB copy related. The N5200 can pull data off a USB device you plug in. If you put a memory stick in, it can pull the data off to back it up or share it across the network. Quite handy. It also functions as a USB drive, you plug it in and it works. Want a 2TB USB stick that won't fit in your pocket? Thecus can help.

Both of these functions have the only real usability problems of the unit, partitioning. The USB drive and target are both located in their own folders. It would be really handy to specify that they go to an existing folder or better yet, a subfolder, but this does not appear to be an option. This is a minor annoyance.

The major annoyance is that for the USB drive capability, you must partition the drive at format time, The USB side can not see the main partition, but you can map a PC to see the USB partition if you know the paths, I found them buried in the docs.

While this would normally dismay me a bit, judging by the huge progress made from the N4100 to the N5200, it is obvious Thecus is listening to concerns and serious about improvement. I would think this will be fixed before the next generation comes out, or better yet in a BIOS upgrade. To me, this is the biggest flaw of the system, but it is eminently fixable.

Last up, one pat on the back to Thecus. All of their devices run Linux, and Thecus is being a very good corporate citizens about their use of GPL'd code. Normally, you only hear about people violating the GPL or have to search their site for a buried link to the source.

With Thecus, the opposite is true. They put the code on their main page, usually right next to the firmware updates themselves. I actually saw the code before I realized what it was, quite an unusual situation. It was a case of me scratching my head wondering what the .GPL extension was before it dawned on me. Again well done.

So, what do we have with the Thecus N5200 RouStor? A box that is better in every way than it's predecessor, faster, better laid out, and hugely more user friendly. Thecus took almost every rough spot on the N4100 and polished them down. Other than the USB problems, there was nothing this box did that wasn't vastly improved.

A year ago, the N4100 was a $700 unit. Now it is a $450 box and the N5200 is a $700 machine. The excellent Western Digital 500GB RE2 drives are about $200, so you can replicate the 2TB RAID 5 machine I built for less than $1700. If you are looking to get a geek you know and love a gift this ChaunaKwanzaMas, anyone I know would be delighted to get one of these.

Basically, two thumbs up: easy to set up, easy to figure out, easy to use. There were a few very minor warts left, but if we weren't testing, we never would have noticed them much less had any problems. Bring on the inevitable N6300. µ