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drueter
Contributor
Contributor

Impaired Disk Transfer Rate after Network Transfer

Running VMWare Workstation 6.5.2 (build-156735) on XP Pro SP3 for both host and guest.

I am trying to copy a large file (9 gig) from the virtual disk of the VM to a share on the host machine.

The transfer begins fine, but then slows to a crawl. I have determined that the physical hard drive becomes the bottleneck.

After doing extensive diagnostics, I have found that the disk transfer rate drops down to 2.8 MB / second, and stays there even after the VM is shut down and VMWare Workstation is closed. Only a physical reboot of the host will restore the disk transfer rate to a normal 100 MB / second. This is a dual-core system, and in Task Manager one CPU is pegged at 100% during all subsequent disk transfers.

This is very reproducible, and I have attached a couple of graphs of disk transfer rates (after a clean boot, and after the failure followed by both shutting down the VM and exiting VMWare Workstation).

The problem exists even after disabling all VMWare NICs except for the bridged NIC (to rule out any problem with VMnet1 or VMnet8).

Hardware is a Dell Optiplex GX620 with Intel 945 chipset. On-board NIC is a Broadcom NetXtreme 57xx. All drivers have been updated to the latest OEM versions.

Transfer to the same share from a different physical machine (without VMWare running) does not exhibit any problems.

Transfer to a USB drive attached to the VM also does not manifest the problem.

Any clues on what could be causing the problem or how to solve?

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2 Replies
drueter
Contributor
Contributor

Just to close the loop on this: the transfer rate problem turned out to be caused by the hard drive controller falling back to PIO mode (instead of using DMA).

Further investigation revealed hard drive controller errors in the Windows system event log. Eventually the problem was determined to be hardware-related: the motherboard (Dell GX620) had bad capacitors. Replacing the motherboard solved the problem.

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kingneutron
Expert
Expert

--Thanks for letting us know; that's good info. Smiley Happy

./. If you have appreciated my response, please remember to apply Helpful/Correct points. TIA

./. If you have appreciated my response, please remember to apply Helpful/Correct points. TIA
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