Open Stack

Hi,

Debian testing (jessie) is now frozen, so it seems a good time to use it as
a base for an OpenStack deployment. Debian jessie provides OpenStack
Icehouse packages from official repos, backported repos are no longer
needed.

Installation procedure works fine in a setup with OVS and GRE tunnels, but
a very low bandwidth is found between instances and routers. I know this is
a frequently asked topic, but after reading some related threads and bugs,
different causes and solutions where shown.

In order to find the problem, several test with iperf has been made and
proposed solutions applied:

1. Bandwidth between two instances running on the same compute node: 2.77
Gbits/sec
2. Bandwidht between compute node and network node (Gigabith Ethernet
used): 941 Mbits/sec
3. Bandwidth between an instance and a router running on network node: 200
Kbits/sec !!!
4. After applying proposed solution setting instance MTU to 1454, identical
result was obtained.
5. After applying proposed solution setting GRO off to physical interfaces
(network and compute nodes), identical result was obtained.

A solution was found here: https://bugs.launchpad.net/fuel/+bug/1256289

6. After setting tcp segmentation offload off in internal router interface:

ip netns exec qrouter-XXXXXX ethtool -K qr-14460da5-08 tso off

Bandwidth increased to 27 Mbits/sec

7. After setting  tcp segmentation offload off in the instance interface, a
very good performance is achieved: 776 Mbits/sec.

Solution found :), but the question is: What's the best way to implement
it? It isn't a practical solution to modify instance Ethernet configuration
after an instance is launched.

Any tip on this?

Thanks!

Alberto
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstack.org/pipermail/openstack/attachments/20141109/14c04ae6/attachment.html>