virt-install<\/code> command with a set of parameters that may vary depending on each case. Here is an example of a simple command to create a virtual machine:<\/p>\n\r\nvirt-install --name=vm1 --memory 2048 --vcpus=12 --cdrom=\/media\/admin\/Files\/downloads\/debian-12.5.0-amd64-DVD-1.iso --disk\/media\/admin\/Files\/vdiskpool1\/vm1vdisk.qcow2 --os-variant=debian12 --debug\r\n<\/pre>\nWe will discuss the --vcpus<\/code> parameter. If the value exceeds the number of host threads, a warning is displayed in the terminal:<\/p>\n\r\n[Tue, Jul 02 2024 12:53:57 virt-install 80478] DEBUG (osdict:216) No recommended value found for key='n-cpus', using minimum=1 * 2\r\n<\/pre>\nTo change the parameters of the virtual machines that have already been created, edit their configuration file stored in the directory \/etc\/libvirt\/qemu\/<\/code>. To open the file, execute the following command:<\/p>\n\r\nsudo nano [vmname].xml\r\n<\/pre>\nwhere
\n[vmname]<\/code> \u2014 the name of the virtual machine.<\/p>\nFind the following line in the file:<\/p>\n
<vcpu placement='static'>N<\/vcpu><\/code><\/p>\nwhere
\nN<\/code> \u2014 the number of virtual threads.<\/p>\nChange the value of N<\/code> and save the file. This is how a part of the configuration file looks like:<\/p>\n\r\n\r\n vm1<\/name>\r\nbb122f07-a85b-44f0-af2c-ecf4a3e5f5f2<\/uuid>\r\n \r\n\t\r\n \t\r\n\t<\/libosinfo:libosinfo>\r\n <\/metadata>\r\n 2097152<\/memory>\r\n 2097152<\/currentMemory>\r\n 12<\/vcpu>\r\n \r\n\thvm<\/type>\r\n\t\r\n <\/os>\r\n<\/pre>\n\nPlease note that no warnings will be displayed if you change the parameters of the virtual machine that has already been configured.\n<\/div>\n
Xen<\/h4>\n
In the case of the Xen hypervisor, vCPU overcommitment is disabled by default due to activated protection. If you try to start a virtual machine with vCPU overcommitment while protection is still on, the machine simply will not start, and a pop-up window with an error message will be displayed (if Xen is used with a GUI):<\/p>\n
\r\nHOST_NOT_ENOUGH_PCPUS - 15 - 8\r\n<\/pre>\nor an error message will be displayed in the terminal (if Xen is used without a GUI):<\/p>\n
\r\nCannot start here [Not enough CPUs (VM needs 12, but host has 4)]\r\n<\/pre>\nIf protection against vCPU overcommitment is disabled, this feature works similarly to the KVM hypervisor: if the total number of vCPUs exceeds the total number of pCPUs on the host machine (cluster), a warning about overcommitment and possible performance degradation will be displayed.<\/p>\n
VMware ESXi<\/h4>\n
By default, vCPU overcommitment is disabled, but you may need to check the overcommitment settings of the clusters that are already running. To do it, you need to enable VMware Distributed Resource Scheduler (DRS):<\/p>\n
\n- Open a web browser and log in to VMware vSphere Client.<\/li>\n
- Click on Hosts and Clusters<\/strong> in the navigation panel to open the list of clusters and hosts.<\/li>\n
- Right-click on the name of the cluster, and select Settings<\/strong> in the context menu.<\/li>\n
- In the panel that opens at the top, go to the Configure<\/strong> tab, and navigate to Service \u2192 vSphere DRS<\/strong>.<\/li>\n
- Click EDIT<\/strong> at the end of the line vSphere DRS is Turned OFF<\/strong>.<\/li>\n
- Toggle the vSphere DRS<\/strong> switch in the Edit Cluster Settings<\/strong> pop-up.<\/li>\n<\/ol>\n
Without leaving the Edit Cluster Settings<\/strong> window, go to the Additional Options<\/strong> tab and activate the Enabled<\/strong> parameter in the CPU Over-Commitment<\/strong> section. To disable overcommitment, set the Over-commitment ratio<\/strong> to 1. <\/p>\nVirtualBox<\/h4>\n
In the VirtualBox hypervisor, everything is similar to KVM: vCPU overcommitment works automatically. If the number of vCPUs across all virtual machines exceeds the number of physical threads in the cluster, a warning about overcommitment and potential performance degradation will be displayed. vCPU adjustment is done manually.<\/p>\n
Hyper-V<\/h4>\n
The interface of the Microsoft Hyper-V hypervisor has a separate tab for configuring vCPU and vRAM.<\/p>\n
To disable overcommitment, go to the virtual machine settings. In the Hardware<\/strong> tab, double-click on the Processor<\/strong> option (or click the +<\/strong> button next to the Processor<\/strong> option), navigate to the NUMA<\/strong> section, and click the Use hardware topology<\/strong> button. The parameters for the maximum allocation of vCPUs and vRAM will take the value of the cluster and cannot exceed it.<\/p>\nMTU<\/h3>\nWindows<\/h4>\n
To configure the MTU parameter on Windows, you need to execute several commands. First, you should check the current value by running the command:<\/p>\n
\r\nnetsh interface ipv4 show subinterfaces\r\n<\/pre>\nNext, change the value according to your needs by executing the following command:<\/p>\n
\r\nnetsh interface ipv4 set subinterface [network interface] mtu=[value] store=persistent\r\n<\/pre>\nwhere:<\/p>\n
\n[network interface]<\/code> \u2014 the name of the network interface;<\/li>\n[value]<\/code> \u2014 the MTU value in bytes.<\/li>\n<\/ul>\nHere is an example of the command that changes the MTU value to 1350 bytes:<\/p>\n
\r\nnetsh interface ipv4 set subinterface Ethernet mtu=1350 store=persistent\r\n<\/pre>\nLinux<\/h4>\n
To change the MTU parameter, you need to edit the file dhclient.conf<\/b> in the directory \/etc\/dhcp\/<\/b>. To edit this file, use the following command:<\/p>\n\r\nsudo nano \/etc\/dhcp\/dhclient.conf\r\n<\/pre>\nNow, you need to add the following text right after the line send host-name = gethostname ();<\/code><\/p>\n\r\ndefault interface-mtu [value];\r\nsupersede interface-mtu [value];\r\n<\/pre>\nwhere:<\/p>\n
[value]<\/code> \u2014 the value of the MTU parameter in bytes.<\/p>\nThese changes will affect all system network interfaces, but if you need to change the MTU value only for some network interfaces, add the following text:<\/p>\n
\r\ninterface \"[network interface]\" {\r\ndefault interface-mtu [value];\r\nsupersede interface-mtu [value];\r\n}\r\n<\/pre>\nwhere:<\/p>\n
\n[network interface]<\/code> \u2014 the name of the network interface;<\/li>\n[value]<\/code> \u2014 the MTU value in bytes.<\/li>\n<\/ul>\nThe following is the example of a text for changing the MTU value to 1350 bytes for the enp1s0<\/strong> interface:<\/p>\n\r\ninterface \"enp1s0\" {\r\ndefault interface-mtu 1350;\r\nsupersede interface-mtu 1350;\r\n}\r\n<\/pre>\nAfter making changes, save and close the file. To apply the values, restart the network service with the command:<\/p>\n
\r\nsudo service networking restart\r\n<\/pre>\nRun this command to check your changes:<\/p>\n
\r\nip a | grep mtu\r\n<\/pre>\nOne should also consider the case when the network is configured with netplan<\/b>. To change the parameter, you need to edit the .yaml<\/b> configuration file in the \/etc\/netplan\/<\/code> directory. There may be multiple configuration files, but by default, there is only one file named 01-network-manager-all.yaml<\/b>. You can create your own .yaml file with a new name and network settings. Example of the source file:<\/p>\n\r\nnetwork:\r\n version: 2\r\n renderer: NetworkManager\r\n ethernets:\r\n enp1s0:\r\n dhcp4: true\r\n dhcp6: true\r\n bridges:\r\n br0:\r\n interfaces: [enp1s0]\r\n dhcp4: true\r\n dhcp6: true\r\n<\/pre>\nIn this case, we will change the MTU parameter of the enp1s0<\/code> network interface. To do it, just add the following text under the interface name:<\/p>\n\r\nmtu: 1350\r\n<\/pre>\nIn this case, the MTU parameter of the enp1s0<\/code> interface will be changed to 1350<\/code>. The final text of the configuration file is as follows:<\/p>\n\r\nnetwork:\r\n version: 2\r\n renderer: NetworkManager\r\n ethernets:\r\n enp1s0:\r\n mtu: 1350\r\n dhcp4: true\r\n dhcp6: true\r\n bridges:\r\n br0:\r\n interfaces: [enp1s0]\r\n dhcp4: true\r\n dhcp6: true\r\n<\/pre>\nTo apply changes, run these commands:<\/p>\n
\r\nsudo netplan apply\r\nsudo systemctl restart networking\r\n<\/pre>\nTo verify the changes, execute:<\/p>\n
\r\nip a | grep mtu\r\n<\/pre>\nTraffic marking<\/h3>\nWindows<\/h4>\n
Traffic marking on Windows is controlled with the “QoS Packet Scheduler” component. To mark packets, enable the packet scheduler and set the marking rules.<\/p>\n
\n- Check if QoS Packet Scheduler<\/b> is enabled in the network interface properties.<\/li>\n
- If it is not enabled, you need to create a new branch HKLM\\SYSTEM\\CurrentControlSet\\services\\Tcpip\\QoS<\/b> in the Windows registry with the string parameter Do not use NLA<\/b> set to 1<\/b>.<\/li>\n<\/ol>\n
Traffic prioritization is configured in TrueConf Server for Windows by default. Just enable the packet scheduler as described above. You can find more details on configuring QoS for Windows in our article<\/a>. <\/p>\nLinux<\/h4>\n
On Linux, traffic marking for TrueConf Server is done by changing the following parameters:<\/p>\n
\n- QoS TC Stream Value<\/b> \u2014 media traffic;<\/li>\n
- QoS TC Transport Value<\/b> \u2014 signaling traffic.<\/li>\n<\/ol>\n
You need to change these parameters in the server configuration with the tc_regkey<\/b> tool.<\/p>\n
First, run the following command to check if any changes in traffic marking have already been made in the configuration:<\/p>\n
\r\nsudo \/opt\/trueconf\/server\/bin\/vcs\/tc_regkey export Configuration - | grep \"QoS\"\r\n<\/pre>\nTwo possible results may be displayed in the terminal:<\/p>\n
\n- Empty, indicating that no changes have been made to the traffic marking configuration.<\/li>\n
- If any changes have been made to the configuration, the result will be as follows:
\n,QoS TC Stream Value, i32, 7<\/code><\/li>\n<\/ol>\nwhere:<\/p>\n
\nQoS TC Stream Value<\/code> \u2014 parameter name;<\/li>\ni32<\/code> \u2014 data type;<\/li>\n7<\/code> \u2014 current value.<\/li>\n<\/ul>\nBefore making changes, stop the server service with the command:<\/p>\n
\r\nsudo systemctl stop trueconf\r\n<\/pre>\nFor example, by default, TrueConf Server uses the value 40 for marking media traffic. To set a different value, run the command:<\/p>\n
\r\nsudo \/opt\/trueconf\/server\/bin\/vcs\/tc_regkey set Configuration \"QoS TC Stream Value\" i32 50\r\n<\/pre>\nwhere:<\/p>\n
\nQoS TC Stream Value<\/code> \u2014 the name of the parameter, in this case, it is media traffic;<\/li>\ni32<\/code> \u2014 data type;<\/li>\n50<\/code> \u2014 new value of traffic priority.<\/li>\n\nIf you need to configure the parameter responsible for marking signaling traffic, the steps are similar; just replace QoS TC Stream Value<\/code> with QoS TC Transport Value<\/code>.<\/p>\nAfter making changes, restart the service with the command:<\/p>\n
\r\nsudo systemctl start trueconf\r\n<\/pre>\nRun this command to check your changes: <\/p>\n
\r\nsudo \/opt\/trueconf\/server\/bin\/vcs\/tc_regkey export Configuration - | grep \"QoS\"\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"This article will show how the settings of dedicated virtualization resources affect the performance of a video conferencing server. We will also offer recommendations for the optimal hypervisor configurations to be used with TrueConf Server.<\/p>\n","protected":false},"author":73,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false,"footnotes":""},"categories":[260],"tags":[191],"class_list":["post-32185","post","type-post","status-publish","format-standard","hentry","category-knowledge-base","tag-deployment","wpautop"],"_links":{"self":[{"href":"https:\/\/trueconf.com/blog\/wp-json\/wp\/v2\/posts\/32185","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/trueconf.com/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/trueconf.com/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/trueconf.com/blog\/wp-json\/wp\/v2\/users\/73"}],"replies":[{"embeddable":true,"href":"https:\/\/trueconf.com/blog\/wp-json\/wp\/v2\/comments?post=32185"}],"version-history":[{"count":8,"href":"https:\/\/trueconf.com/blog\/wp-json\/wp\/v2\/posts\/32185\/revisions"}],"predecessor-version":[{"id":43140,"href":"https:\/\/trueconf.com/blog\/wp-json\/wp\/v2\/posts\/32185\/revisions\/43140"}],"wp:attachment":[{"href":"https:\/\/trueconf.com/blog\/wp-json\/wp\/v2\/media?parent=32185"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/trueconf.com/blog\/wp-json\/wp\/v2\/categories?post=32185"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/trueconf.com/blog\/wp-json\/wp\/v2\/tags?post=32185"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}