Network drives....where does all the BW go?

[KJ3N]

'Cuz I didn't have gigabit ethernet.

I DID get a 10x increase from 10/100 ethernet, but 10x Suck is still suck!

Well, let me give some informal results of my tests. Parameters are as follows:

1Gb 16-port NetGear network switch
One ActionTek wireless router running 802.11b/g
One desktop PC with a 802.11b/g wireless card
One Novell NW6.5 server with 10/100Mb ethernet PCI card
One desktop PC with onboard 1Gb ethernet card
Cat-5e cabling for the wired part of my network

Transfer a 225MB from the Novell server to MyBook using desktop PC with wireless 802.11b/g: Sustained transfer rate of 17Mbps. Time to complete file transfer was 4.5 minutes

Transfer 496MB file from Novell server to MyBook using desktop PC with onboard 1 Gb ethernet card: Sustained transfer rate of 125Mbps. Time to complete transfer was under 2 minutes.

Transfer 699MB file directly from desktop with wireless to MyBook: Sustained transfer rate of 18Mbps. Time to complete transfer was 6 minutes 13 seconds.

Transfer 3.46GB file directly from desktop PC with onboard 1Gb ethernet card to MyBook: Sustained transfer rate in excess of 300Mbps (with peaks as high as 380Mbps). Time to complete transfer was under 2 minutes.

Based on the above tests, the results you experienced, Paul, are due entirely to the USB to ethernet adapter bottleneck. If you had a router with wireless capability, you'd be better off plugging the MyBook into the router and using wireless on a laptop.

JMO

Any time you put something in the path, it adds latency, and hence slow down. USB isn't directly connected to the bus. PCI(x, e, etc) is. So, you added a whole lot of overhead by using USB instead of an PCI card.

What Corey said.

[W1GUH]

Or....decide not to use an ethernet drive? Remember?

[N1LAF]

Keep in mind that a 100Mbps is only 10Mbytes per second tops, without the overhead

USB 2.0 is only 480 Mbps, which is 48 Mbytes/sec
ATA133 (Parallel Interfaced Hard drives) is 133Mbytes/sec(Interface), while the drive internal rate is only like 44 Mbytes/sec. This is why Caches cache size are important.

USB 3.0 is rated at 5Gbps, or 600 Mbytes/sec. To fully utilize the transfer rate, PCI Express x4 will be needed, 4 lanes with 250 Mbyte/sec per lane transfer.

There are two things to consider. Latency effect is in terms of delay, Overhead is in terms of loss due to format and signalling.

You may question some of my math, which I can explain simply, that in asynchronous serial transmissions, 8b10b encode/decode are most likely used, meaning that sending a byte will use 10 bits. Bit patterns are needed to keep the bias, or 'carrier', neutral.