Slow Network Performance with Multiple Clients

Hi,

I have 5 clients that copies large files (300-500 MB) onto a server at the
same time... I teamed 3 NICs on the Win2k3 server (SLA). When i start copying
with 2 clients everything looks good 20MB/s transfer on each client and i get
40+% on network performance....

Problems begin when i start the 3rd.... network performance halts down to
~<5% and everything slows down to 8 MB/s transfer.... when i get to 5
clients, its dragging along at 3-5 MB/s.... network performance jumps up and
down from 40% to ~<3%.... everything is on Gigabit Managed Switch and NICs.

Could the hardware do this? the drive array is raid5.... but it looks like a
software issue since everything works fine when i only have 2 clients.

Thanks,
Dennis

It looks as if there could be a couple of causes, but right off the bat I see
that you are asking your HD to write 5 seperate files averaging 400MB apiece
all at the same time. Seems like a lot to ask of the hardware. Is there any
way you can stagger the client uploads? The data is only going to move
through as fast as it can be written once the buffer gets full.

"DTK" wrote:

> Hi,
>
> I have 5 clients that copies large files (300-500 MB) onto a server at the
> same time... I teamed 3 NICs on the Win2k3 server (SLA). When i start copying
> with 2 clients everything looks good 20MB/s transfer on each client and i get
> 40+% on network performance....
>
> Problems begin when i start the 3rd.... network performance halts down to
> ~<5% and everything slows down to 8 MB/s transfer.... when i get to 5
> clients, its dragging along at 3-5 MB/s.... network performance jumps up and
> down from 40% to ~<3%.... everything is on Gigabit Managed Switch and NICs.
>
> Could the hardware do this? the drive array is raid5.... but it looks like a
> software issue since everything works fine when i only have 2 clients.
>
> Thanks,
> Dennis

I understand that its still limited to the harddrive write speed. However,
once I add the third computer to the process of copying files, everything
slows down.... Under network performance of the server suddenly drops from
40% all the way down.

shouldn't it stay at about 40%? or some saturation point?

"SeriousSam" wrote:

> It looks as if there could be a couple of causes, but right off the bat I see
> that you are asking your HD to write 5 seperate files averaging 400MB apiece
> all at the same time. Seems like a lot to ask of the hardware. Is there any
> way you can stagger the client uploads? The data is only going to move
> through as fast as it can be written once the buffer gets full.
>
> "DTK" wrote:
>
> > Hi,
> >
> > I have 5 clients that copies large files (300-500 MB) onto a server at the
> > same time... I teamed 3 NICs on the Win2k3 server (SLA). When i start copying
> > with 2 clients everything looks good 20MB/s transfer on each client and i get
> > 40+% on network performance....
> >
> > Problems begin when i start the 3rd.... network performance halts down to
> > ~<5% and everything slows down to 8 MB/s transfer.... when i get to 5
> > clients, its dragging along at 3-5 MB/s.... network performance jumps up and
> > down from 40% to ~<3%.... everything is on Gigabit Managed Switch and NICs.
> >
> > Could the hardware do this? the drive array is raid5.... but it looks like a
> > software issue since everything works fine when i only have 2 clients.
> >
> > Thanks,
> > Dennis