.. _system_option: ###### Option ###### This chapter describe the possibilities of advanced system behavior. ******* General ******* .. cfgcmd:: set system option ctrl-alt-delete Action which will be run once the ctrl-alt-del keystroke is received. .. cfgcmd:: set system option reboot-on-panic Automatically reboot system on kernel panic after 60 seconds. .. cfgcmd:: set system option startup-beep Play an audible beep to the system speaker when system is ready. .. cfgcmd:: set system option root-partition-auto-resize Enables the root partition auto-extension and resizes to the maximum available space on system boot. Kernel ====== .. cfgcmd:: set system option kernel disable-mitigations Disable all optional CPU mitigations. This improves system performance, but it may also expose users to several CPU vulnerabilities. This will add the following option to the Kernel commandline: * ``mitigations=off`` .. note:: Setting will only become active with the next reboot! .. cfgcmd:: set system option kernel disable-power-saving Disable CPU power saving mechanisms also known as C states. This will add the following two options to the Kernel commandline: * ``intel_idle.max_cstate=0`` Disable intel_idle and fall back on acpi_idle * ``processor.max_cstate=1`` Limit processor to maximum C-state 1 .. note:: Setting will only become active with the next reboot! *********** HTTP client *********** .. cfgcmd:: set system option http-client source-address
Several commands utilize cURL to initiate transfers. Configure the local source IPv4/IPv6 address used for all cURL operations. .. cfgcmd:: set system option http-client source-interface Several commands utilize curl to initiate transfers. Configure the local source interface used for all CURL operations. .. note:: `source-address` and `source-interface` can not be used at the same time. ********** SSH client ********** .. cfgcmd:: set system option ssh-client source-address
Use the specified address on the local machine as the source address of the connection. Only useful on systems with more than one address. .. cfgcmd:: set system option ssh-client source-interface Use the address of the specified interface on the local machine as the source address of the connection. *************** Keyboard Layout *************** When starting a VyOS live system (the installation CD) the configured keyboard layout defaults to US. As this might not suite everyones use case you can adjust the used keyboard layout on the system console. .. cfgcmd:: set system option keyboard-layout Change system keyboard layout to given language. Defaults to ``us``. .. note:: Changing the keymap only has an effect on the system console, using SSH or Serial remote access to the device is not affected as the keyboard layout here corresponds to your access system. .. _system_options_performance: *********** Performance *********** As more and more routers run on Hypervisors, expecially with a :abbr:`NOS (Network Operating System)` as VyOS, it makes fewer and fewer sense to use static resource bindings like ``smp-affinity`` as present in VyOS 1.2 and earlier to pin certain interrupt handlers to specific CPUs. We now utilize `tuned` for dynamic resource balancing based on profiles. .. stop_vyoslinter .. seealso:: https://access.redhat.com/sites/default/files/attachments/201501-perf-brief-low-latency-tuning-rhel7-v2.1.pdf .. start_vyoslinter .. cfgcmd:: set system option performance < throughput | latency > Configure one of the predefined system performance profiles. * ``throughput``: A server profile focused on improving network throughput. This profile favors performance over power savings by setting ``intel_pstate`` and ``max_perf_pct=100`` and increasing kernel network buffer sizes. It enables transparent huge pages, and uses cpupower to set the performance cpufreq governor. It also sets ``kernel.sched_min_granularity_ns`` to 10 us, ``kernel.sched_wakeup_granularity_ns`` to 15 uss, and ``vm.dirty_ratio`` to 40%. * ``latency``: A server profile focused on lowering network latency. This profile favors performance over power savings by setting ``intel_pstate`` and ``min_perf_pct=100``. It disables transparent huge pages, and automatic NUMA balancing. It also uses cpupower to set the performance cpufreq governor, and requests a cpu_dma_latency value of 1. It also sets busy_read and busy_poll times to 50 us, and tcp_fastopen to 3.