Hello. We are currently building up a new CloudStack KVM cluster with OpenVSwitch as the network backing and we are faced with some conflicting information we would be grateful to have a second opinion on.
In Red Hat documentation[1], a following quote is said: > Do not use LACP with OVS-based bonds, as this configuration is problematic > and unsupported. Instead, consider using bond_mode=balance-slb as a > replacement for this functionality. > [...] > For the technical details behind this requirement, see BZ#1267291. The linked bug report is made for RHEL 7.0 base and was closed in 2017. From what we see, the issue does no longer seem actual. We put this to the test ourselves in our lab, configured OVSBond interfaces with LACP and didn't see any issues at first glance. Our lab environment used OVS Bonds with lacp=active and bond_mode=balance-slb. Our experience shows that if we configure a bond without LACP, there is high risk for L2 loops and we do not wish to risk that. We do not see how suggesting balance-slb is a solution for lack of LACP. Is anyone else using LACP+balance-slb with OVS Bonds? Does anyone have actual scenarios where this has been an actual problem? Are we going to run into any predictable failure here by going this route? In an another Red Hat documentation page[2], following remarks are made about balance-slb OVS Bond mode: > Performance is affected by extra parsing per packet. Is there any known metric for how big the performance overhead is? How much of a resource are we sacrificing by using balance-slb? > There is a potential for vhost-user lock contention. "vhost-user lock contention" - it is not entirely clear what the risk here is. We found vague references in qemu documentation only, but that didn't tell us anything much. What would the real-world impact be here? [1] [ https://docs.redhat.com/en/documentation/red_hat_openstack_platform/8/html/director_installation_and_usage/appe-bonding_options#appe-Bonding_Options | https://docs.redhat.com/en/documentation/red_hat_openstack_platform/8/html/director_installation_and_usage/appe-bonding_options#appe-Bonding_Options ] [2] [ https://docs.redhat.com/en/documentation/red_hat_openstack_platform/10/html/advanced_overcloud_customization/appe-bonding_options | https://docs.redhat.com/en/documentation/red_hat_openstack_platform/10/html/advanced_overcloud_customization/appe-bonding_options ] Lugupidamisega / Best regards, Joann Mõndresku Süsteemiadministraator | Systems Administrator | jo...@wavecom.ee WaveCom AS | ISO 9001, 27001 & 27017 Certified DC and Cloud services Endla 16, Tallinn 10142 | www.wavecom.ee | www.facebook.com/wavecom.ee
