N5200 Slow Network Reads

[BlkAdder]

I have a Thecus N5200 running firmware 1.00.08 with 5 x Seagate 500GB ST3500630AS ( according to the disk info menu ) in a RAID 5 configuration. I have it connected to a managed 10/100 Nortel Baystack 450-24T switch which all my other computers are connected to as well ( all Windows XP with latest patches ). Port statistics say there are no Ethernet level errors occurring. Don't know if this is normal, but there is an "!" on the right hand side of the front display.

The problem is when trying to playback video files from the N5200, very frequently I experience buffer underuns and the video stream pauses or breaks up till it can rebuffer enough data to continue which can take 10 seconds. The video streams only need about 1Mb - 10Mb/sec to play, but I seem unable to sustain that on a constant basis. I am the only person using the unit and have tried plugging it in to a D-Link gig switch, but that didn't help. Strange thing is uploading files happens very fast and I am quite happy with the performance in that direction, but it typically takes upwards of 6 minutes to copy 700MB off the unit. The RAID information screen says the array is healthy and there is nothing in the system logs to say there is a problem. Any assistance/suggestions with this problem would be appreciated.

[DR]

Very strange, you tried doing it direct form the back of the unit to your PC?

[BlkAdder]

Can't say I have tried that yet... I can give that a try later on tonight.

[DR]

Give it a go - it then isolates the network as being an issue or the Thecus.

[BRoche]

About the ! have a look here
http://forums.hexus.net/showpost.php...91&postcount=6

[BlkAdder]

That solves one of my long-time problems. Thanks! Never could find an explanation as to what that "!" was on the LCD anywhere.

[rosenbagel]

Have you tried turning on jumbo frames? I don't think that works with 10/100 switches but since you have a gig switch, it could be what you need to get better performance.

caveat: this could thwack your ability to access the thecus via the internet (as your ISP might not be compatible with jumbo frames)

But, worth a try...

[BlkAdder]

Tried jumbo frames, looks like 4k frames are the best the switch can handle... Helped a bit. But what it did lead me to is checking my NIC drivers... For some reason they are Microsoft's drivers for the NIC's, not the manufacturer. I am going to update the NIC drivers and see if that helps any.

P.S. Connecting the computer directly to the NAS did not help any. But if it is a NIC driver problem that would explain a lot.

[static_167]

I have a similar problem with moving files. Coping to the N5200BR is fine but coping back from it takes forever.
firmware 1.00.10
RAID 5 - 5 x Seagate 400GB ST3400620AS
i.e. 1gig file copy to -> approx 2 minutes, same file from it, anywhere between 11-15 minutes.
I know what the cause is though.. I have a Netgear WGU624 patched into one of the LAN ports acting as an access point, if I remove it the transfer back drops to normal i.e. 2 minutes.
As the WGU624 has no ability to check the LAN ports for errors or speed and duplex, I cannot tell whats happening to it. As far as the supposed 4 port switch on the N5200BR which is actually a hub, a SNMP query shows no errors/drops etc.. on the interface. For the mean time I can live with disconnecting the Netgear.

Dave

[BlkAdder]

Well, on one of my systems, switching to full gig speeds ( without jumbo packets for now ) has certainly helped. My main system is now benching 250Mb/sec down and about 120Mb/sec up. Using jumbo frames might get this going even higher. It was the shoddy Microsoft NIC drivers that I replaced that fixed it on that system. On my secondary system I put an Intel 1000MT NIC in, but it did not help that system any. Transfers go between 5 - 15Mb/sec at best. I'll give that one a reload of XP tonight and see if that perks it up.

[brfindla]

Are you sure about those speeds? 250 MB/s?
How did you benchmark that? Forgive me if I have bad math, but 1GB = 1000,000 bits =~ 120MB

Then there is overhead of the transport protocol, the theoretical maximum of the medium, etc.. I don't know for sure but I would guess *MAYBE* it was possible to hit a little more than half of this.

Is that a math error, or is something else going on here I don't understand?

Thanks,

Brian

[BlkAdder]

Network bandwidth is measured in bits per second, not bytes which is used for something like storage capacity of hard drives. The small "b" on the end of Mb stands for bits, a capital B would mean bytes. So my benchmark of 250Mb/sec = 250,000,000 bits/sec, divide by 8 bits per byte gives you 31,250,000 Bytes/sec or 31.25MB/sec. Max theoretical speed for gig Ethernet ( not that you would reach it with protocol overheads, switching times and inefficiencies ) is 125,000,000 Bytes/sec, so my benchmarked speed is only 25% of maximum gig speeds.

Basic Ethernet = 10Mb or 10,000,000 bits/sec or 1.25MB/sec
Fast Ethernet = 100Mb or 100,000,000 bits/sec or 12.5MB/sec
Gig Ethernet = 1,000Mb or 1,000,000,000 bits/sec or 125MB/sec
10 Gig Ethernet = 10,000Mb or 10,000,000,000 bits/sec or 1250MB/sec

Hope that makes sense.