Slow transfer rates on N5550 - possible causes?

[dancinbear]

I just got my N5550 yesterday and had a lot of fun getting it set up last night. I love it, except for one key feature: all data transfers have been unexpectedly slow. I get around 4 MB/s, regardless of RAID configuration (I've tried JBOD, RAID 0 and RAID 6), connection protocol (I've tried AFP and SMB), or performance test (I've tried AJA, HELIOS, and just copying files and watching MenuMeters).

Does anyone have any suggestions on what I could try to improve performance?

I've done some searching and it looks like it's often caused by the disks in use. These are the four at my disposal:

Samsung HD103UJ, 1TB (Listed as supported on the compatibility list from Thecus)
(2x) WDC WD10EACS-00D, 1TB (Not Listed)
WDC WD20EARS-00S, 2TB (Not Supported/Recommended)

I tried just making a JBOD volume from the first disk only (the Samsung), but it still had the same transfer rates. Below are the results of my performance testing. All tests were done to an iMac wired using Cat6 to an unmanaged gigabit switch where both the computer and the N5550 are wired.

RAID 0 (Disks 1 and 2) over AFP:
https://www.dropbox.com/s/1vx71lt6zwoieio/Thecus%20RAID%200%20AFP%20-%20AJA.png?dl=0

RAID 0 (Disks 1 and 2) over SMB:
https://www.dropbox.com/s/21pvbpp4shd7333/Thecus%20RAID%200%20SMB%20-%20AJA.png?dl=0

RAID 6 (Disks 1,2,3,4) over AFP:
https://www.dropbox.com/s/9qmchyzcdy9d3n0/Thecus%20RAID%206%20AFP%20-%20AJA.png?dl=0

RAID 6 (Disks 1,2,3,4) over SMB:
https://www.dropbox.com/s/tl5phqc1i6yqhdc/Thecus%20RAID%206%20SMB%20-%20AJA.png?dl=0

Do I really need to go get 5 WD Red drives, or are there configuration things I could try?

 

[dancinbear]

Last night I tried plugging my computer directly into the N5550 (manual IPs on both machines) and discovered a transfer rate much more in line with my expectations (60 MB/s write, 70 MB/s read over AFP). I was able to get the same transfer rate on both WAN1/LAN1 and LAN2 ports. I figured it must be something bad with my network configuration, so I plugged my computer and the NAS back into the same places they were before. This time, however, I got great transfer rates.

The only possible cause I can come up with is that there seems to be an issue with DNS inside my network. My modem (U-verse fiber) responds with two IPs for the N5550, only one of which is correct. Perhaps this was causing the issue? I'm not sure I'll ever know for sure.

So the problem is solved, but is no less a mystery.

 

[stevech]

Were you doing intra-LAN transfers to measure speeds? I assume so, given the rates.

If so, the DNS would not be involved if you are using numeric LAN IP addresses for your tests - which it seems you'd have to be doing.

WD red drives: From what I read, these have the same performance as consumer priced drives but red gets you a supposed longer warranty. To me, that's useless because all the drive vendors just give you a "reconditioned" drive on an RMA.

 

[dancinbear]

Were you doing intra-LAN transfers to measure speeds? I assume so, given the rates.

If so, the DNS would not be involved if you are using numeric LAN IP addresses for your tests - which it seems you'd have to be doing.

WD red drives: From what I read, these have the same performance as consumer priced drives but red gets you a supposed longer warranty. To me, that's useless because all the drive vendors just give you a "reconditioned" drive on an RMA.

I was doing intra-LAN transfers. At first, I was using the hostname to connect, which is why I thought DNS might be interfering (the incorrect IP it was returning was for the gateway). After this experience, I have decided to just define a static IP for the NAS and always use IP to connect.

The biggest difference I could see between the WD NAS-enabled drives and their consumer drives was WD's warning against using consumer drives in NASes. I found it in the footnotes of Thecus' hard drive compatibility list:

Thecus HD compatibility list:
http://www.thecus.com/download/comp..._N4800Eco_N5550_N4510U_N7510_HDD_SSD_list.pdf

WD consumer drive warning:
http://wdc.custhelp.com/app/answers/detail/a_id/1397