Web Hosting Talk : Web Hosting Main Forums : Hosting Security and Technology : Weird issue copying files over 1 gig network

[MGCJerry]

I recently added a new server to my LAN that has a 1gig network card and I've encountered a problem with copying large files between the new server and my machine which also is supposed to have a 1gig network card.

However, when trying to copy a 2.34GB file from "my machine" to the new machine, the file takes about 2 minutes to copy.

The SAME file copied from the new server to my machine takes about 40 seconds.

There is obviously a bottleneck somewhere and my suspicion is that it is on "my machine" having problems sending the file. I have attached a LAN usage from task manager. I've played with my network card settings such as jumbo frame size, checksum offload, etc and the speed still drops as shown in the attached images and just spikes here and there. I've even tried matching the settings on the server with the same effect.

My machine -> server = SLOW (slowcopy.gif)
Server -> My machine = FAST (fastcopy.gif)

My machine:
WinXP Pro
Intel Q8200 Quad core 2.1GHz
4GB RAM (only 2G being seen)
SATA 2 Drive

Server:
Win2k3 Standard
Intel Xeon MP Quad 3.0GHz (HT disabled)
16GB RAM (only 3G being seen)
SCSI Ultra3 10k rpm, 4 disk RAID5 Array using hardware RAID controller with onboard battery & 64MB RAM

Thanks in advance.

[MGCJerry]

Just an update on this.

I have found that my SATA-2 drive can write 10 times faster than it can read. So far, I'm not impressed with SATA, I may go back to legacy IDE mode and forgo the hot swap capability.

[UNIXy]

Originally Posted by MGCJerry

Just an update on this.

I have found that my SATA-2 drive can write 10 times faster than it can read.

I find it interesting that you mention this. Are you sure it's not the OS? I'm not familiar with the intricacies of Windows but it's known that a process write is ALWAYS faster than a read. Here's why. When a programs reads a file, it will block until it's read all the data it needs. On the other hand, the process doesn't have to wait until a write is done (unless it has to read it back!). The notion is a bit confusing at first but it sinks in after a while.

Anyway, back to the problem. When you're copying from the server to the machine, which is faster, perhaps the server is using the available RAM (3.5GB) to cache a large portion of it in memory. Whereas your machine can only see 2GB, which isn't enough to cache most of the file. Try installing a 64-bit OS on the Q8200 and try again (Is the Q8200 one of those gateway workstations?).

Regards
Joe / UNIXY

[MGCJerry]

It probably is Windows being stupid, but installing a 64bit OS to see if transfer speeds improve over a network is kind of extreme. Plus, I don't own a 64bit OS.

I've tried the same thing with a smaller 1.04GB file and it still drops out when trying to copy it from my machine to the server and it ends up taking 3 minutes. Copying that from the server to my machine takes about a minute.

I also redone all of my network setup last night, tried using known good cables, reinstalling network & disk controller drivers on all machines to no avail. The only thing that "fixes" this dropout problem with copying large files is setting my machine's network speed to "100mbit full duplex". Which I'm willing to live with because its still a few minutes faster than the "auto-negotiate" setting which ends up being "1gbit".

No, my machine is not a gateway workstation. The Q8200 is the lower end Intel Quad CPU. Anyway with the /3G switch, my winxp machine sees 3.25GB of RAM.

Thanks for the info and help Joe.

I'm willing to live with my solution of setting my machine's network speed to 100mbit.