Are there in oVirt any limitations on network interfaces?
Hi, We are experiencing some network limitations on our virtual machines, we have done some initial testing to pinpoint the exact issue. Hardware: 2 x 25G NICs per physical machine 2 x 100G interlinks between datacenters iPerf test between two VMs in same host on same cluster and same datacenter reveals ~20GB/s (what is more or less expected) iPerf test between two VMs in differet host on same cluster and same datacenter reveals ~20GB/s (what is more or less expected) iPerf test between two VMs in differet host on different cluster and different datacenter reveals ~10GB/s (what is half or less than expected) There are no firewalls or other identified blockeing equipment between the datacenters. The only difference, as I see it, are traffic going across the 100G interlinks. Are there anything that needs to be tuned / setup in the NICs either on the VM or the host to be able to get higher speed between the datacenters? /John
Hi John, Your question is interesting. Are you handing the physical card to the VM (passthrough) or using the VirtIO driver? How is the MTU configuration of your interfaces on the host? BR. Em ter., 12 de mar. de 2024 às 11:32, John Mortensen <jpm@b4restore.com> escreveu:
Hi, We are experiencing some network limitations on our virtual machines, we have done some initial testing to pinpoint the exact issue. Hardware: 2 x 25G NICs per physical machine 2 x 100G interlinks between datacenters
iPerf test between two VMs in same host on same cluster and same datacenter reveals ~20GB/s (what is more or less expected) iPerf test between two VMs in differet host on same cluster and same datacenter reveals ~20GB/s (what is more or less expected) iPerf test between two VMs in differet host on different cluster and different datacenter reveals ~10GB/s (what is half or less than expected)
There are no firewalls or other identified blockeing equipment between the datacenters.
The only difference, as I see it, are traffic going across the 100G interlinks. Are there anything that needs to be tuned / setup in the NICs either on the VM or the host to be able to get higher speed between the datacenters?
/John _______________________________________________ Users mailing list -- users@ovirt.org To unsubscribe send an email to users-leave@ovirt.org Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/HAJBDJVKH3KCTG...
-- Att, Jorge Visentini +55 55 98432-9868
Hi Jorge, We're using the VirtIO driver, the MTU is 9000 and the physical NICs are 25G. The ports are grouped in bonds. ( 2 x 25G interfaces in a bond ) After additional tests we have seen the following: * between vm's on same host - speed is as expected * between vm's on different hosts in same cluster - speed is as expected * between vm's on different hosts and in different cluster - speed is much lower than expected. I was curious why the speed drops when we go across clusters, and was wondering if there are some limitations cluster wide or some tuning cluster wide that could be tweaked. /John /John
That’s sounding more likely to be the network between the clusters/DCs than your ovirt setup. Ovirt clusters are just logical groupings, they don’t manage any networking directly themselves. Some questions to ask: - Does the inter cluster link have a lower than 9000 mtu? - What’s the latency between your clusters? - What’s the bandwidth between them (ie, are you tunneling over the internet or do you have 200G of private fiber between them)? - does the carrier between clusters have a lower MTU? -Darrell
On Mar 15, 2024, at 7:48 AM, John Mortensen <jpm@b4restore.com> wrote:
Hi Jorge, We're using the VirtIO driver, the MTU is 9000 and the physical NICs are 25G. The ports are grouped in bonds. ( 2 x 25G interfaces in a bond ) After additional tests we have seen the following: * between vm's on same host - speed is as expected * between vm's on different hosts in same cluster - speed is as expected * between vm's on different hosts and in different cluster - speed is much lower than expected. I was curious why the speed drops when we go across clusters, and was wondering if there are some limitations cluster wide or some tuning cluster wide that could be tweaked. /John
/John _______________________________________________ Users mailing list -- users@ovirt.org To unsubscribe send an email to users-leave@ovirt.org Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/XNNYC7MXPDPD5I...
participants (3)
-
Darrell Budic -
John Mortensen -
Jorge Visentini