Possible bottlenecks on a gigabit network?

[deanx0r]

I just recently upgraded my router with a new gigabit one and I can never seem to get past 500mbps when transferring to my WHS machine. Is this kind of performance expected in the real world or am I running against a few bottlenecks on the network?

Could it be the NIC from the WHS which is an integrated Realtek on a Gigabyte G41 motherboard, or the type of cables I use (under 50ft cat5e)?

 

[fluffmonster]

harddrive IO becomes the bottleneck if the network is otherwise working correctly. WD green drives, for example, just top 110MB/s or so for their fastest operation, not enough to use even a quarter of "gigabit" theoretical capacity. This is slower than a 7200rpm drive will manage, but it illustrates the point.

 

[Crusty]

harddrive IO becomes the bottleneck if the network is otherwise working correctly. WD green drives, for example, just top 110MB/s or so for their fastest operation, not enough to use even a quarter of "gigabit" theoretical capacity. This is slower than a 7200rpm drive will manage, but it illustrates the point.

1gbps = 1000mbps = 125MB/s
A WD Green drive should be able to saturate most of a gigabit link in a perfect scenario.

 

[imagoon]

1gbps = 1000mbps = 125MB/s
A WD Green drive should be able to saturate most of a gigabit link in a perfect scenario.

A perfect scenario that never happens.

 

[RadiclDreamer]

harddrive IO becomes the bottleneck if the network is otherwise working correctly. WD green drives, for example, just top 110MB/s or so for their fastest operation, not enough to use even a quarter of "gigabit" theoretical capacity. This is slower than a 7200rpm drive will manage, but it illustrates the point.

I think you are confusing bits and bytes

 

[imagoon]

WHS also does some tricks with the files. I think it stages to your system disk so if you are like some sane people and load the system disk with the 'small' drive and then add large ones after you could be slowed by the system disk. Also the nics, switches and cables do tend to matter.

I would guess disk I/O is the first issue, but check the CPU load also. The Nics can play a big roll depending on buffers and offload support and all that.

 

[JackMDS]

I just recently upgraded my router with a new gigabit one and I can never seem to get past 500mbps

That is very nice, most end_user give out Cigars :hmm: if they achieve similar "Speed".

 

[Nothinman]

1gbps = 1000mbps = 125MB/s
A WD Green drive should be able to saturate most of a gigabit link in a perfect scenario.

But don't forget to subtract the overhead of SMB/CIFS which is relatively high for a file transfer protocol.

 

[Crusty]

But don't forget to subtract the overhead of SMB/CIFS which is relatively high for a file transfer protocol.

Of course, I was just pointing out how he's confused bits for bytes

 

[Nothinman]

Of course, I was just pointing out how he's confused bits for bytes

True. That and the fact that any one of a dozen other things the OS does for performance reasons may have any number of unintended side-effects for certain workloads.

 

[deanx0r]

WHS also does some tricks with the files. I think it stages to your system disk so if you are like some sane people and load the system disk with the 'small' drive and then add large ones after you could be slowed by the system disk. Also the nics, switches and cables do tend to matter.

I would guess disk I/O is the first issue, but check the CPU load also. The Nics can play a big roll depending on buffers and offload support and all that.

All the drives are Samsung F3EG 2TB. I know they can push over 100MB/s and I was expecting to get around 75-85% of my gigabit bandwidth. But at roughly 500mbps, I have my doubts about the overhead being that inefficient.

I am running a E6600, so I definitively have the CPU power. Are cat5e cables able to sustain Gb networks? I am starting to think the integrated Realtek NIC might just not be up to the task. I wonder if it can also be the Intel G41 express chipset that is holding the whole system back.

 

[imagoon]

All the drives are Samsung F3EG 2TB. I know they can push over 100MB/s and I was expecting to get around 75-85% of my gigabit bandwidth. But at roughly 500mbps, I have my doubts about the overhead being that inefficient.

I am running a E6600, so I definitively have the CPU power. Are cat5e cables able to sustain Gb networks? I am starting to think the integrated Realtek NIC might just not be up to the task. I wonder if it can also be the Intel G41 express chipset that is holding the whole system back.

The nic may be the issue. That disk you listed is peak 110MB/s Vally is 55MB/s. Throw in some random I/O and your numbers are a bit closer to making sense. Maybe still a bit slow though. Random access of 15ms can be a bit killer.

 

[Tsavo]

I quit using all crappy onboard NICs and went to Intel's stuff. I've got decently fast spindle discs and I can sustain close to 80 MB/s whereas those onboard NICs could barely keep 55 MB's going for long. The main drive in the other PC can probably only manage 80 MB/s sustained so I could realistically grab another 5 MB/s by getting another F3.

 

[Emulex]

smb2 or nfs nfs comes with every windows desktop and nfs server with every server o/s. just not very routable. udp is nice.

turn off nagle - and tweak the ack ratio - nagle will give you some nasty choppy results when it kicks in

 

[Nothinman]

nfs comes with every windows desktop

And it sucks very bad.

 

[Crusty]

Most definitely a problem of the onboard Realtek. Without fail I've only been able to get Intel NIC's to saturate a gigabit link with ease.

Don't forget PCI bandwidth is only 133MB/s so if any other devices are using PCI you're going to be limited if your NIC uses that bus as well. I'm not sure how the NIC's are attached on modern boards, but I always use an addin PCI-E Intel NIC.

 

[JackMDS]

I get from Onboards Realtek Giga NICs 70MB/Sec. transfer.

That is B=Byte I know the difference.

Entry Level Giga Rating on peer-to-peer Network is like Wireless doing 300 feet indoor.

The two variables that effect it most are the quality of the Giga switch and the TCP/IP stack parameters.

And then is varies a lot depending on general Network activity.

 

[fluffmonster]

okay, failed to properly distinguish B vs. b. mea culpa.

Still, when i transfer files from my samba fileserver (w/ WD greens and intel nic) to my PC (on-board realtek), I only get about 50% network utilization (read from task manager). This is about what I expected really.

Here's a curious thing though...when I transfer large files from my PC to the fileserver, network utilization bounces up and down from 60% down to very little and back and forth. What is going on with that?