Ethernet to USB 2.o is slow...how fix?

[jtsnow]

When I send data over my home LAN ethernet to a hard drive running on a USB
2.0 its very slow data transfer. This is PC to PC over 100baseT wired home
LAN to do disk backups. The slowness occurs in the translation from
10baseT100 to the USB 2.0 and the CPU is 100% utilized.

Are there cards that offload the CPU processing needed to do this
translation?

I have a PCI combo card (w/firewire), brand new installed.

The following clues narrow the problem down to the USB to ethernet
conversion as the problem.:

PC to PC over ethernet from installed HD to installed HD is very fast.
PC from its own C: drive to the USB 2.0 drive is very fast.
but when do PC to PC over ethernet to save data on theh USB 2.0 drive its
very very slow...like 5x slower then drive C: to USB 2.0.

Any thoughts?

 

[CWatters]

When I send data over my home LAN ethernet to a hard drive running on a USB
2.0 its very slow data transfer. This is PC to PC over 100baseT wired home
LAN to do disk backups. The slowness occurs in the translation from
10baseT100 to the USB 2.0 and the CPU is 100% utilized.

I have a similar set up. Every night two PC are imaged to the USB drive
connected to one of them using DriveImage/Ghost.

The directly connected PC backs up and verifies a 13GByte image in 39mins =
about 5.7MByte/S

The one connected via the LAN backs up and verifies 9.5GByte in 60mins =
about 2.7MByte/S

So something is slowing things down by a factor of about 2.

How does that compare with what you see?

Colin

 

[CWatters]

How does that compare with what you see?

Colin

Ah I see you get a factor of 5.

 

[jtsnow]

yea i think so. sounds like just something you have to live with with usb
I use ghost too
thx

 

[Andrew Rossmann]

[This followup was posted to comp.sys.ibm.pc.hardware.storage and a copy
was sent to the cited author.]

When I send data over my home LAN ethernet to a hard drive running on a USB
2.0 its very slow data transfer. This is PC to PC over 100baseT wired home
LAN to do disk backups. The slowness occurs in the translation from
10baseT100 to the USB 2.0 and the CPU is 100% utilized.

Are there cards that offload the CPU processing needed to do this
translation?

I have a PCI combo card (w/firewire), brand new installed.

The following clues narrow the problem down to the USB to ethernet
conversion as the problem.:

PC to PC over ethernet from installed HD to installed HD is very fast.
PC from its own C: drive to the USB 2.0 drive is very fast.
but when do PC to PC over ethernet to save data on theh USB 2.0 drive its
very very slow...like 5x slower then drive C: to USB 2.0.

Any thoughts?

Do the USB and network card use the same interrupt? It's possible
there is too much on one interrupt, slowing things down.

What is the CPU load when copying between HD's over the network (NOT
to the USB drive)? Maybe the network card drivers are sucking up too
much CPU.

 

[CWatters]

PC to PC over ethernet from installed HD to installed HD is very fast.
PC from its own C: drive to the USB 2.0 drive is very fast.
but when do PC to PC over ethernet to save data on theh USB 2.0 drive its
very very slow...like 5x slower then drive C: to USB 2.0.

Any thoughts?

I read somewhere that shared folders can cause increased network traffic and
this did once cause me a problem..

If I remember correctly the explanation went like this.... Every time one
PC writes to a shared folder all the others are notified that a change has
occured. Presumably this allows them to update any open explorer windows. I
took this to mean that a problem could arrise if one PC writes small amounts
of data very frequently. Each byte written might cause a small burst of
activity as all the other PCs are notified of the change.

In my case I could write to my USB 2.0 drive from the directly connected PC
but my wifes PC couldn't do the same over our LAN. Every few GB I would get
a Delayed Write failure which made backing up her drive impossible.

To fix the problem all I had to do was restructure the folders I was using
and "push the share down a level"....

Before (with the problem)...
===================

I had a shared folder in the route of the external drive E: called
"Backups". I arranged for PC1 to write to subfolder "Backups\PC1" and PC2 to
write to "Backups\PC2" etc. PC1 never had no problem but PC2 got Delayed
Write failed errors every few GByte or so.

After (problem fixed)....
================

I removed the share from "Backups" and shared "Backups\PC2 only". The folder
"Backups\PC1" does not actually need to be shared as only PC1 writes to it.
This was enough to fix the Delayed Write failed errors I was seeing.

The above was quite repeatable. If I put it back the way it was the error
came back.

Colin