[ovirt-users] Re: Question about OVN MTU
On Fri, Oct 30, 2020 at 8:14 PM Strahil Nikolov wrote: > If you mean "Administration" -> "Providers" -> "Ovirt-provider-ovn" -> it > is enabled. > > Yes, this one. If it is enabled, Engine should reflect the MTU which is provided by ovirt-provider-ovn via OpenStack API. The related configuration value dhcp-mtu of ovirt-provider-ovn is explained in https://github.com/oVirt/ovirt-provider-ovn/blob/master/README.adoc. > Best Regards, > Strahil Nikolov > > > > > > > В петък, 30 октомври 2020 г., 21:10:02 Гринуич+2, Strahil Nikolov < > hunter86...@yahoo.com> написа: > > > > > > Any hint for the location of "Automatic Synchronization" in UI ? > > Best Regards, > Strahil Nikolov > > > > > > > В петък, 30 октомври 2020 г., 20:16:13 Гринуич+2, Dominik Holler < > dhol...@redhat.com> написа: > > > > > > > > On Fri, Oct 30, 2020 at 7:03 PM Strahil Nikolov > wrote: > > in 4.3.10's UI it shows 1500 :) > > > > This might be just a misleading representation of the default value or an > unknown value. > If "Automatic Synchronization" is enabled for the ovirt-provider-ovn in > oVirt Engine, > the value should be updated in Engine to the correct after the next > synchronization in the background. > > > > > > > > > > > > > В петък, 30 октомври 2020 г., 13:25:05 Гринуич+2, Dominik Holler < > dhol...@redhat.com> написа: > > > > > > > > > > > > > > > > On Thu, Oct 29, 2020 at 9:36 PM Alex K wrote: > >> > >> > >> On Tue, Oct 27, 2020, 02:49 Strahil Nikolov via Users > wrote: > >>> Hello All, > >>> > >>> I would like to learn more about OVN and especially the maximum MTU > that I can use in my environment. > >>> > >>> Current Setup 4.3.10 > >>> Network was created via UI -> MTU Custom -> 8976 -> Create on External > Provider -> Connect to Physical Network > >>> > >>> So my physical connection is MTU 9000 and I have read that Geneve uses > 24 bits (maybe that's wrong ?) , thus I have reduced the MTU to 8976. > >> From the internet draft it seems that the tunnel header + reserved bits > comprise 64 bits. A common practice for Geneve implementations is to use > 8900 mtu for VMs when having 9000 mtu physical network. > >> > > > > Ack, this is a safe choice. > > In oVirt's default configuration, an overhead of 58 bytes > > ( = 20 IPv4 header + 8 UDP header + 16 GENEVE Ethernet header (including > 8 bytes options) + 14 bytes inner Ethernet header) > > is added. > > This is why the default MTU for OVN networks in oVirt is 1442 bytes, > which assumes 1500 bytes MTU in the physical network. > > > > > > > >> > >> The draft: > >> https://tools.ietf.org/html/draft-ietf-nvo3-geneve-08 > >>> > >>> I did some testing on the VMs and ping with payload of '8914' was the > maximum I could pass without fragmenting and thus the MTU on the VMs was > set to 8942. > >>> > >>> Did I correctly configure the test network's MTU and am I > understanding it correctly that we need extra 34 bits inside the network > for encapsulation ? > >>> > > > > You could check with packet analyzers like tcpdump and wireshark. > > > >>> I have checked > https://www.ovirt.org/develop/release-management/features/network/managed_mtu_for_vm_networks.html > but I don't see any refference how to calculate the max MTU. > >>> > >>> > >>> Best Regards, > >>> Strahil Nikolov > >>> ___ > >>> Users mailing list -- users@ovirt.org > >>> To unsubscribe send an email to users-le...@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/CKNS5T5KE2W5EIXBTGQDU3URKHQDVAM4/ > >>> > >>> > >> ___ > >> Users mailing list -- users@ovirt.org > >> To unsubscribe send an email to users-le...@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/VIDP3MLYHWG2WXQ6JB6EHK66J5WBOMVT/ > >> > >> > > ___ > > Users mailing list -- users@ovirt.org > > To unsubscribe send an email to users-le...@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/7UN5DXXKXN3KBLTLGXIPTGWVF4ODKKUB/ > > > > > > ___ Users mailing list -- users@ovirt.org To unsubscribe send an email to users-le...@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/LFWBSX5ANBIGVZW5X7ONPUREFYMU4YR7/
[ovirt-users] Re: Question about OVN MTU
If you mean "Administration" -> "Providers" -> "Ovirt-provider-ovn" -> it is enabled. Best Regards, Strahil Nikolov В петък, 30 октомври 2020 г., 21:10:02 Гринуич+2, Strahil Nikolov написа: Any hint for the location of "Automatic Synchronization" in UI ? Best Regards, Strahil Nikolov В петък, 30 октомври 2020 г., 20:16:13 Гринуич+2, Dominik Holler написа: On Fri, Oct 30, 2020 at 7:03 PM Strahil Nikolov wrote: > in 4.3.10's UI it shows 1500 :) > This might be just a misleading representation of the default value or an unknown value. If "Automatic Synchronization" is enabled for the ovirt-provider-ovn in oVirt Engine, the value should be updated in Engine to the correct after the next synchronization in the background. > > > > > > В петък, 30 октомври 2020 г., 13:25:05 Гринуич+2, Dominik Holler > написа: > > > > > > > > On Thu, Oct 29, 2020 at 9:36 PM Alex K wrote: >> >> >> On Tue, Oct 27, 2020, 02:49 Strahil Nikolov via Users >> wrote: >>> Hello All, >>> >>> I would like to learn more about OVN and especially the maximum MTU that I >>> can use in my environment. >>> >>> Current Setup 4.3.10 >>> Network was created via UI -> MTU Custom -> 8976 -> Create on External >>> Provider -> Connect to Physical Network >>> >>> So my physical connection is MTU 9000 and I have read that Geneve uses 24 >>> bits (maybe that's wrong ?) , thus I have reduced the MTU to 8976. >> From the internet draft it seems that the tunnel header + reserved bits >> comprise 64 bits. A common practice for Geneve implementations is to use >> 8900 mtu for VMs when having 9000 mtu physical network. >> > > Ack, this is a safe choice. > In oVirt's default configuration, an overhead of 58 bytes > ( = 20 IPv4 header + 8 UDP header + 16 GENEVE Ethernet header (including 8 > bytes options) + 14 bytes inner Ethernet header) > is added. > This is why the default MTU for OVN networks in oVirt is 1442 bytes, which > assumes 1500 bytes MTU in the physical network. > > > >> >> The draft: >> https://tools.ietf.org/html/draft-ietf-nvo3-geneve-08 >>> >>> I did some testing on the VMs and ping with payload of '8914' was the >>> maximum I could pass without fragmenting and thus the MTU on the VMs was >>> set to 8942. >>> >>> Did I correctly configure the test network's MTU and am I understanding it >>> correctly that we need extra 34 bits inside the network for encapsulation ? >>> > > You could check with packet analyzers like tcpdump and wireshark. > >>> I have checked >>>https://www.ovirt.org/develop/release-management/features/network/managed_mtu_for_vm_networks.html >>> but I don't see any refference how to calculate the max MTU. >>> >>> >>> Best Regards, >>> Strahil Nikolov >>> ___ >>> Users mailing list -- users@ovirt.org >>> To unsubscribe send an email to users-le...@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/CKNS5T5KE2W5EIXBTGQDU3URKHQDVAM4/ >>> >>> >> ___ >> Users mailing list -- users@ovirt.org >> To unsubscribe send an email to users-le...@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/VIDP3MLYHWG2WXQ6JB6EHK66J5WBOMVT/ >> >> > ___ > Users mailing list -- users@ovirt.org > To unsubscribe send an email to users-le...@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/7UN5DXXKXN3KBLTLGXIPTGWVF4ODKKUB/ > > ___ Users mailing list -- users@ovirt.org To unsubscribe send an email to users-le...@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/PIC2CYCXCVPKSVQJVQFFCXITEG5YTK6N/
[ovirt-users] Re: Question about OVN MTU
Any hint for the location of "Automatic Synchronization" in UI ? Best Regards, Strahil Nikolov В петък, 30 октомври 2020 г., 20:16:13 Гринуич+2, Dominik Holler написа: On Fri, Oct 30, 2020 at 7:03 PM Strahil Nikolov wrote: > in 4.3.10's UI it shows 1500 :) > This might be just a misleading representation of the default value or an unknown value. If "Automatic Synchronization" is enabled for the ovirt-provider-ovn in oVirt Engine, the value should be updated in Engine to the correct after the next synchronization in the background. > > > > > > В петък, 30 октомври 2020 г., 13:25:05 Гринуич+2, Dominik Holler > написа: > > > > > > > > On Thu, Oct 29, 2020 at 9:36 PM Alex K wrote: >> >> >> On Tue, Oct 27, 2020, 02:49 Strahil Nikolov via Users >> wrote: >>> Hello All, >>> >>> I would like to learn more about OVN and especially the maximum MTU that I >>> can use in my environment. >>> >>> Current Setup 4.3.10 >>> Network was created via UI -> MTU Custom -> 8976 -> Create on External >>> Provider -> Connect to Physical Network >>> >>> So my physical connection is MTU 9000 and I have read that Geneve uses 24 >>> bits (maybe that's wrong ?) , thus I have reduced the MTU to 8976. >> From the internet draft it seems that the tunnel header + reserved bits >> comprise 64 bits. A common practice for Geneve implementations is to use >> 8900 mtu for VMs when having 9000 mtu physical network. >> > > Ack, this is a safe choice. > In oVirt's default configuration, an overhead of 58 bytes > ( = 20 IPv4 header + 8 UDP header + 16 GENEVE Ethernet header (including 8 > bytes options) + 14 bytes inner Ethernet header) > is added. > This is why the default MTU for OVN networks in oVirt is 1442 bytes, which > assumes 1500 bytes MTU in the physical network. > > > >> >> The draft: >> https://tools.ietf.org/html/draft-ietf-nvo3-geneve-08 >>> >>> I did some testing on the VMs and ping with payload of '8914' was the >>> maximum I could pass without fragmenting and thus the MTU on the VMs was >>> set to 8942. >>> >>> Did I correctly configure the test network's MTU and am I understanding it >>> correctly that we need extra 34 bits inside the network for encapsulation ? >>> > > You could check with packet analyzers like tcpdump and wireshark. > >>> I have checked >>>https://www.ovirt.org/develop/release-management/features/network/managed_mtu_for_vm_networks.html >>> but I don't see any refference how to calculate the max MTU. >>> >>> >>> Best Regards, >>> Strahil Nikolov >>> ___ >>> Users mailing list -- users@ovirt.org >>> To unsubscribe send an email to users-le...@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/CKNS5T5KE2W5EIXBTGQDU3URKHQDVAM4/ >>> >>> >> ___ >> Users mailing list -- users@ovirt.org >> To unsubscribe send an email to users-le...@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/VIDP3MLYHWG2WXQ6JB6EHK66J5WBOMVT/ >> >> > ___ > Users mailing list -- users@ovirt.org > To unsubscribe send an email to users-le...@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/7UN5DXXKXN3KBLTLGXIPTGWVF4ODKKUB/ > > ___ Users mailing list -- users@ovirt.org To unsubscribe send an email to users-le...@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/ITSJKVNYAZ3NVL4BRXPASAFSYCHCWFV5/
[ovirt-users] Re: Question about OVN MTU
On Fri, Oct 30, 2020 at 7:03 PM Strahil Nikolov wrote: > in 4.3.10's UI it shows 1500 :) > > This might be just a misleading representation of the default value or an unknown value. If "Automatic Synchronization" is enabled for the ovirt-provider-ovn in oVirt Engine, the value should be updated in Engine to the correct after the next synchronization in the background. > > > > > > В петък, 30 октомври 2020 г., 13:25:05 Гринуич+2, Dominik Holler < > dhol...@redhat.com> написа: > > > > > > > > On Thu, Oct 29, 2020 at 9:36 PM Alex K wrote: > > > > > > On Tue, Oct 27, 2020, 02:49 Strahil Nikolov via Users > wrote: > >> Hello All, > >> > >> I would like to learn more about OVN and especially the maximum MTU > that I can use in my environment. > >> > >> Current Setup 4.3.10 > >> Network was created via UI -> MTU Custom -> 8976 -> Create on External > Provider -> Connect to Physical Network > >> > >> So my physical connection is MTU 9000 and I have read that Geneve uses > 24 bits (maybe that's wrong ?) , thus I have reduced the MTU to 8976. > > From the internet draft it seems that the tunnel header + reserved bits > comprise 64 bits. A common practice for Geneve implementations is to use > 8900 mtu for VMs when having 9000 mtu physical network. > > > > Ack, this is a safe choice. > In oVirt's default configuration, an overhead of 58 bytes > ( = 20 IPv4 header + 8 UDP header + 16 GENEVE Ethernet header (including 8 > bytes options) + 14 bytes inner Ethernet header) > is added. > This is why the default MTU for OVN networks in oVirt is 1442 bytes, which > assumes 1500 bytes MTU in the physical network. > > > > > > > The draft: > > https://tools.ietf.org/html/draft-ietf-nvo3-geneve-08 > >> > >> I did some testing on the VMs and ping with payload of '8914' was the > maximum I could pass without fragmenting and thus the MTU on the VMs was > set to 8942. > >> > >> Did I correctly configure the test network's MTU and am I understanding > it correctly that we need extra 34 bits inside the network for > encapsulation ? > >> > > You could check with packet analyzers like tcpdump and wireshark. > > >> I have checked > https://www.ovirt.org/develop/release-management/features/network/managed_mtu_for_vm_networks.html > but I don't see any refference how to calculate the max MTU. > >> > >> > >> Best Regards, > >> Strahil Nikolov > >> ___ > >> Users mailing list -- users@ovirt.org > >> To unsubscribe send an email to users-le...@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/CKNS5T5KE2W5EIXBTGQDU3URKHQDVAM4/ > >> > >> > > ___ > > Users mailing list -- users@ovirt.org > > To unsubscribe send an email to users-le...@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/VIDP3MLYHWG2WXQ6JB6EHK66J5WBOMVT/ > > > > > ___ > Users mailing list -- users@ovirt.org > To unsubscribe send an email to users-le...@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/7UN5DXXKXN3KBLTLGXIPTGWVF4ODKKUB/ > > ___ Users mailing list -- users@ovirt.org To unsubscribe send an email to users-le...@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/7N4Z4SYIRJ44BASOTVKCABV4QG53U3C6/
[ovirt-users] Re: Question about OVN MTU
in 4.3.10's UI it shows 1500 :) В петък, 30 октомври 2020 г., 13:25:05 Гринуич+2, Dominik Holler написа: On Thu, Oct 29, 2020 at 9:36 PM Alex K wrote: > > > On Tue, Oct 27, 2020, 02:49 Strahil Nikolov via Users wrote: >> Hello All, >> >> I would like to learn more about OVN and especially the maximum MTU that I >> can use in my environment. >> >> Current Setup 4.3.10 >> Network was created via UI -> MTU Custom -> 8976 -> Create on External >> Provider -> Connect to Physical Network >> >> So my physical connection is MTU 9000 and I have read that Geneve uses 24 >> bits (maybe that's wrong ?) , thus I have reduced the MTU to 8976. > From the internet draft it seems that the tunnel header + reserved bits > comprise 64 bits. A common practice for Geneve implementations is to use > 8900 mtu for VMs when having 9000 mtu physical network. > Ack, this is a safe choice. In oVirt's default configuration, an overhead of 58 bytes ( = 20 IPv4 header + 8 UDP header + 16 GENEVE Ethernet header (including 8 bytes options) + 14 bytes inner Ethernet header) is added. This is why the default MTU for OVN networks in oVirt is 1442 bytes, which assumes 1500 bytes MTU in the physical network. > > The draft: > https://tools.ietf.org/html/draft-ietf-nvo3-geneve-08 >> >> I did some testing on the VMs and ping with payload of '8914' was the >> maximum I could pass without fragmenting and thus the MTU on the VMs was set >> to 8942. >> >> Did I correctly configure the test network's MTU and am I understanding it >> correctly that we need extra 34 bits inside the network for encapsulation ? >> You could check with packet analyzers like tcpdump and wireshark. >> I have checked >>https://www.ovirt.org/develop/release-management/features/network/managed_mtu_for_vm_networks.html >> but I don't see any refference how to calculate the max MTU. >> >> >> Best Regards, >> Strahil Nikolov >> ___ >> Users mailing list -- users@ovirt.org >> To unsubscribe send an email to users-le...@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/CKNS5T5KE2W5EIXBTGQDU3URKHQDVAM4/ >> >> > ___ > Users mailing list -- users@ovirt.org > To unsubscribe send an email to users-le...@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/VIDP3MLYHWG2WXQ6JB6EHK66J5WBOMVT/ > > ___ Users mailing list -- users@ovirt.org To unsubscribe send an email to users-le...@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/7UN5DXXKXN3KBLTLGXIPTGWVF4ODKKUB/ ___ Users mailing list -- users@ovirt.org To unsubscribe send an email to users-le...@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/LJIZN5QBUVJTO3O5XWPN7HRG3IBMGI5L/
[ovirt-users] Re: Question about OVN MTU
On Thu, Oct 29, 2020 at 9:36 PM Alex K wrote: > > > On Tue, Oct 27, 2020, 02:49 Strahil Nikolov via Users > wrote: > >> Hello All, >> >> I would like to learn more about OVN and especially the maximum MTU that >> I can use in my environment. >> >> Current Setup 4.3.10 >> Network was created via UI -> MTU Custom -> 8976 -> Create on External >> Provider -> Connect to Physical Network >> >> So my physical connection is MTU 9000 and I have read that Geneve uses 24 >> bits (maybe that's wrong ?) , thus I have reduced the MTU to 8976. >> > From the internet draft it seems that the tunnel header + reserved bits > comprise 64 bits. A common practice for Geneve implementations is to use > 8900 mtu for VMs when having 9000 mtu physical network. > > Ack, this is a safe choice. In oVirt's default configuration, an overhead of 58 bytes ( = 20 IPv4 header + 8 UDP header + 16 GENEVE Ethernet header (including 8 bytes options) + 14 bytes inner Ethernet header) is added. This is why the default MTU for OVN networks in oVirt is 1442 bytes, which assumes 1500 bytes MTU in the physical network. > The draft: > https://tools.ietf.org/html/draft-ietf-nvo3-geneve-08 > >> >> I did some testing on the VMs and ping with payload of '8914' was the >> maximum I could pass without fragmenting and thus the MTU on the VMs was >> set to 8942. >> >> Did I correctly configure the test network's MTU and am I understanding >> it correctly that we need extra 34 bits inside the network for >> encapsulation ? >> >> You could check with packet analyzers like tcpdump and wireshark. > I have checked >> https://www.ovirt.org/develop/release-management/features/network/managed_mtu_for_vm_networks.html >> but I don't see any refference how to calculate the max MTU. >> >> >> Best Regards, >> Strahil Nikolov >> ___ >> Users mailing list -- users@ovirt.org >> To unsubscribe send an email to users-le...@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/CKNS5T5KE2W5EIXBTGQDU3URKHQDVAM4/ >> > ___ > Users mailing list -- users@ovirt.org > To unsubscribe send an email to users-le...@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/VIDP3MLYHWG2WXQ6JB6EHK66J5WBOMVT/ > ___ Users mailing list -- users@ovirt.org To unsubscribe send an email to users-le...@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/7UN5DXXKXN3KBLTLGXIPTGWVF4ODKKUB/
[ovirt-users] Re: Question about OVN MTU
On Tue, Oct 27, 2020, 02:49 Strahil Nikolov via Users wrote: > Hello All, > > I would like to learn more about OVN and especially the maximum MTU that I > can use in my environment. > > Current Setup 4.3.10 > Network was created via UI -> MTU Custom -> 8976 -> Create on External > Provider -> Connect to Physical Network > > So my physical connection is MTU 9000 and I have read that Geneve uses 24 > bits (maybe that's wrong ?) , thus I have reduced the MTU to 8976. > >From the internet draft it seems that the tunnel header + reserved bits comprise 64 bits. A common practice for Geneve implementations is to use 8900 mtu for VMs when having 9000 mtu physical network. The draft: https://tools.ietf.org/html/draft-ietf-nvo3-geneve-08 > > I did some testing on the VMs and ping with payload of '8914' was the > maximum I could pass without fragmenting and thus the MTU on the VMs was > set to 8942. > > Did I correctly configure the test network's MTU and am I understanding it > correctly that we need extra 34 bits inside the network for encapsulation ? > > I have checked > https://www.ovirt.org/develop/release-management/features/network/managed_mtu_for_vm_networks.html > but I don't see any refference how to calculate the max MTU. > > > Best Regards, > Strahil Nikolov > ___ > Users mailing list -- users@ovirt.org > To unsubscribe send an email to users-le...@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/CKNS5T5KE2W5EIXBTGQDU3URKHQDVAM4/ > ___ Users mailing list -- users@ovirt.org To unsubscribe send an email to users-le...@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/VIDP3MLYHWG2WXQ6JB6EHK66J5WBOMVT/
[ovirt-users] Re: Question about OVN MTU
Erm... noone ? Best Regards, Strahil Nikolov В вторник, 27 октомври 2020 г., 02:51:00 Гринуич+2, Strahil Nikolov via Users написа: Hello All, I would like to learn more about OVN and especially the maximum MTU that I can use in my environment. Current Setup 4.3.10 Network was created via UI -> MTU Custom -> 8976 -> Create on External Provider -> Connect to Physical Network So my physical connection is MTU 9000 and I have read that Geneve uses 24 bits (maybe that's wrong ?) , thus I have reduced the MTU to 8976. I did some testing on the VMs and ping with payload of '8914' was the maximum I could pass without fragmenting and thus the MTU on the VMs was set to 8942. Did I correctly configure the test network's MTU and am I understanding it correctly that we need extra 34 bits inside the network for encapsulation ? I have checked https://www.ovirt.org/develop/release-management/features/network/managed_mtu_for_vm_networks.html but I don't see any refference how to calculate the max MTU. Best Regards, Strahil Nikolov ___ Users mailing list -- users@ovirt.org To unsubscribe send an email to users-le...@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/CKNS5T5KE2W5EIXBTGQDU3URKHQDVAM4/ ___ Users mailing list -- users@ovirt.org To unsubscribe send an email to users-le...@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/OBUNKBIIS2R472JD7BZZWTNOVOST5S7B/
