Actually achieving 100MB/sec over network

Mercutio

Mercutio

Mercutio

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Assuming the basic drive throughput needed to achieve over 100MB/sec to the local machine, what's actually needed to pull 100MB/sec over a network?

1) I'm assuming onboard NIC's are a no-no? I can have 2 machines with gigabit network ports next to each other through a gigabit switch and still get rather poor connection speeds.

2) What cabling? Cat5e? Cat6? What's the assumed basic level of cable needed?

3) Configuration. Does jumbo packets need to be setup on all hosts?

Any other thoughts/bits.
 
I have a few computers on a Gb network, Gb switch, cat5 cable all using the onboard NIC's and max out at about 80MB/sec transferring large files.
I think my drives are the limiting factor.
 
I use modern 3TB drives, Netgear switch & Intel gigabit NICs. I can max out the gigabit without tweaking jumbo frames.
 
Cabling will be a big part of it if you want to make the most of gigabit. Onboard NICs usually can manage it sometimes needs tweaking some of the advanced settings for the adapter.

Main issues are the cable quality, any CPU bottlenecks and HDD bottlenecks i.e. a lot of mechanical HDDs struggle to sustain over 80MByte/s sustained write speeds and when dealing with smaller files that will drop a lot from both read and write speeds dropping a lot.
 
CPU bottleneck on 1Gbps LAN? I very much doubt it unless the CPU is at high usage with other things anyway, or the files being copied are being dynamically generated or used at either end.

Gigabit LAN has a theoretical max of 125MB/s, but by the time you've accounted for any other traffic on the network (including things like ARP/DNS packets even when other machines aren't using the network), collisions from various machines and the minute amounts of time lost at either end and each switch for packet switching etc, you end up with the real-world maximum of approx 90-110MB/s depending on configuration. A smaller number of large files will also be faster than a large number of small files.

If you only have 2 machines on the link with decent NIC and a direct connection you can get the higher end of that, but in a more complex network you're going to struggle to sustain more than about 80MB/s consistently and for long periods. It's possible, but only if traffic on the network is low.
 
Well, the setup is pretty much for home use. 2 machines upstairs, a VDSL router on the middle floor and plans to add a media box under the TV and a PC to act as a NAS to follow, hence the questions. I really don't seem to see decent speeds for file transfers though so thought I'd check there was no real extra's.

I'll check my cabling, see if that helps. I am indeed though only expecting around 100MB/sec.
 
Are you confusing MB and Mb? Network speed is measured in Mb and hard disk size is measured in MB. Windows 7 handily converts to give you a reflection of the transfer rate, so if you have a 100Mb network, you would only ever see 12.5MB /s transfer and that would be under ideal conditions. The actual rate you should see would be about 80% of that.
 
Mercutio said:
Assuming the basic drive throughput needed to achieve over 100MB/sec to the local machine, what's actually needed to pull 100MB/sec over a network?

1) I'm assuming onboard NIC's are a no-no? I can have 2 machines with gigabit network ports next to each other through a gigabit switch and still get rather poor connection speeds.

2) What cabling? Cat5e? Cat6? What's the assumed basic level of cable needed?

3) Configuration. Does jumbo packets need to be setup on all hosts?

Any other thoughts/bits.
Click to expand...

1) Onboard NICs are fine

2) Cat5e is the minimum you should be using

3) If you want to use jumbo packets, it needs to be configured on both ends yes (including any switches in-between).

Use something like iperf to test network speeds as it takes HDD speed limitations out of the equation.
 
Imy said:
3) If you want to use jumbo packets, it needs to be configured on both ends yes (including any switches in-between).

Use something like iperf to test network speeds as it takes HDD speed limitations out of the equation.
Click to expand...

Even your router has to support jumbo packets -- basically it's an all-or-nothing situation: if you want jumbo packets, every single device on the network must support them, and in most cases you are always going to have at least one device that doesn't.

100% spot-on on using iperf to confirm network speeds (you must rule out other bottlenecks such as source and destination disk speeds).
 
At the moment I'm struggling to get over 20Mb's to my nas with a gigabyte switch, onboard broadcom gigabit nic and cat5e cabling. The cable is old and not exactly well routed in terms of going alongside power cables and the like, so I'm not sure how much of a difference that makes.

Anyone know the real world difference between a network cable running alongside power cables and other crap and away from everything else, can it make a huge difference or basically not a huge difference.

Not sure how much might be being lost from nas raid performance, its a netgear readynas with 3x2gb drives in their own raid mode. I would expect some performance loss but 20MB's on newer 2gb drives(5400-5900rpm types) seems ridiculously low and pushing over terrabytes of data thats a lot of extra time.

I've had two netgear gigabit switches in the past I dunno however long they've been out and sub £40, they've both died, both run stupidly hot so went with a new low power TP-link one so maybe its the cheapness of the switch, I've bought a Zyxel one as I needed another one for the other end of power line network(the nas/switch/computer direct network cable attached to each other) for multiple devices so was going to swap them over see of a different switch gives more speed.

Where do you start in diagnosing where the slow speed comes from without buying new cables, new switches and new nic's?

Are there any particular onboard nic's that are known to be complete junk and won't have a chance of achieving decent speeds? I was under the impression that Intel>broadcom>realtek from a few websites but no idea if thats true.
 
drunkenmaster said:
At the moment I'm struggling to get over 20Mb's to my nas with a gigabyte switch, onboard broadcom gigabit nic and cat5e cabling. The cable is old and not exactly well routed in terms of going alongside power cables and the like, so I'm not sure how much of a difference that makes.
Click to expand...

You need to rule out the network, so forget about the NAS for a minute. Get two machines with gigabit NICs, and a copy of iperf on each. Run a test between these two computers, and there's your answer.

In terms of interference on an Ethernet cable, it is extremely unlikely. In datacentres you have hundreds of Ethernet and power cables in very close proximity to each other, and things still work fine. The cables inside are twisted, which helps greatly to resist interference.
 
Controllers on NAS are sloooooooooow. Thats why most advertise that they work in RAID to increase the read/write speeds. But you will be lucky to get better than 30MB/s out of a standard NAS enclosure.
 
R088ieS86 said:
Controllers on NAS are sloooooooooow. Thats why most advertise that they work in RAID to increase the read/write speeds. But you will be lucky to get better than 30MB/s out of a standard NAS enclosure.
Click to expand...

That's about all I get from my WD NAS :(

MW
 
Thats why I got a Microserver and steered away from a prebuilt NAS, I often max out the gigabait between my PC (onboard NIC) and my N40L.

HEADRAT
 
A prebuilt NAS doesn't have to be slow. There are plenty of models that will provide excellent performance, but you have to pay for it.

There's no mention of which model the Netgear is, so it's difficult to judge.
 
I max out my Gb network on a regular basis, as in 128MB/s transfer speeds between conputers.

This is all with onboard ports, and through a VM super hub too. It is between a few high capacity drives though, like Seagate 3TB ones.
 
spoffle said:
I max out my Gb network on a regular basis, as in 128MB/s transfer speeds between conputers.

This is all with onboard ports, and through a VM super hub too. It is between a few high capacity drives though, like Seagate 3TB ones.
Click to expand...

Isn't this faster than Gigabit is theoretically capable of?

I though the maximum was about 120MiB/Sec or 125MB/Sec.
 
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