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throughput of tenant network lower than of external network?

asked 2015-06-29 08:50:03 -0500

tab87vn gravatar image

updated 2015-06-29 15:01:11 -0500


I'm doing some traffic measurement on VM instances created in OpenStack Juno. I'm using a standard OpenStack configuration with 3 interfaces: Management, Data and External networks.

The Data (em1) and External (em3) interface have bandwidth of 10Gbps and 1Gbps. So intra-network VMs located in 2 different Compute nodes should have much higher data transfer throughput if they use em1 instead of em3. In other words, connecting to private tenant network IP address (east-west traffic) should be much faster than floating IP.

Weird thing is that, while throughput measured with data transfer using Floating IP (via em3) is about 550-800 Mbps (say, 60-80% of the achievable throughput), the throughput measured via Tenant network (em1) is only ~400Mbps (out of 10Gbps that the host compute node is able to reach).

Anybody could guess what configuration could make it wrong? I personally don't think that OpenStack limits the data tenant interface while maximises external network interface.

Thank you!

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answered 2016-09-12 14:00:26 -0500

ospz2014 gravatar image

any update you got on this, or you were able to deal with it ?

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answered 2016-09-13 00:08:22 -0500

Mohit gravatar image

updated 2016-09-13 00:08:41 -0500

Can you update the MTU parameter set under neutron net-show {your-network-name}

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Asked: 2015-06-29 08:50:03 -0500

Seen: 405 times

Last updated: Sep 13 '16