Procurve 2848 very slow

[Unison]

Guys

Hopefully some one can shed some light on an issue we are having with the Procurve 2848.

If you have two PC's connected to the Procurve and copy a file between them, the performace is of an acceptable level.

If you connect another switch to the Procurve, and move one of the PC's to this switch, then copy the file from the machine connected to the Procurve Switch to the other machine connected to the other switch the performance is really poor (im talking 50 odd seconds for a 50 mb file).

However if I copy a file from the machine that is connected to the other switch to the machine that is connected to the Procurve switch, from the machine that is connected to the procurve switch the performace is acceptable again.

Then I repeated the steps on the machine connected to the other switch and found when coping the file to the machine connected to the Procurve switch the process was quick, when when coping from the machine connected to the Procurve switch the process was slow...

The configuration is the factory default. I have tried disabiling LACP etc, but that made no difference. I have tried sveral different switches as the other switch, still with the same results...

Software revision : I.08.105
ROM Version : I.08.07

Any ideas what would be causing this to occur?

Thanks

David

[Matt Hobbs · Accepted solution]

Hi David,

Try enabling 'qos-passthrough-mode'. It should make a big difference. There are more details on this command in the firmware release notes.

Matt

[Unison]

Hi Matt

Thanks - that got it sorted.

Additional information in case anyone has the same issue...

The port buffering design for the Series 2800 switches has been
optimized for gigabit-to-gigabit traffic flows. For this reason, some
flows from Gigabit-to-100Base or even 100Base-to-10Base may not perform
as well as would be expected. The QOS Pass-Through mode enhancement can
provide a significant performance improvement for high-bandwidth traffic
flows through the 2800 switches, particularly when running traffic flows
from 1000Base to either 100Base or 10Base connections.

QOS Pass-Through mode is OFF by default, and must be enabled via the
"config" context of the CLI by entering the CLI command

# qos-passthrough-mode

followed by

# write memory

and rebooting the switch.

Thanks Again

[Bruce Campbell_3]

Note the cli command:

walkmib ifoutdiscards

will show whether packets are being
dropped because of a lack of output
buffers.

And note don't enable qos-passthrough
if you are using applications
than depend on qos, like voip.

[Unison]

Sorry for the delay in replying. so if one required VoIP type application, along with been able to connect 100mb devices to this switch is that possible?