Essential Linux Kernel Tuning Parameters for Optimal System Performance
This guide lists 44 essential Linux kernel and sysctl parameters, providing their default values and recommended settings to improve memory management, networking, file handling, and overall system stability for production environments and reliability.
vm.swappiness : controls swapping when memory is low; default 60, recommended 10‑30.
vm.overcommit_memory : controls memory overcommit; default 0, recommended 1.
vm.dirty_ratio : dirty page ratio; default 20, recommended 5‑10.
vm.dirty_background_ratio : background dirty page ratio; default 10, recommended 1‑5.
vm.dirty_expire_centisecs : dirty page expiration time; default 3000, recommended 1000‑2000.
vm.dirty_writeback_centisecs : dirty write‑back interval; default 500, recommended 100‑200.
vm.vfs_cache_pressure : kernel cache pressure; default 100, recommended 50‑100.
vm.min_free_kbytes : minimum free memory; default 4096, recommended 65536.
vm.max_map_count : max memory map areas; default 65530, recommended 262144.
net.core.somaxconn : max TCP connection queue; default 128, recommended 1024.
net.core.netdev_max_backlog : network device backlog size; default 1000, recommended 5000.
net.core.rmem_max : max TCP receive buffer; default 212992, recommended 524288.
net.core.wmem_max : max TCP send buffer; default 212992, recommended 524288.
net.ipv4.tcp_fin_timeout : TCP FIN timeout; default 60, recommended 10‑20.
net.ipv4.tcp_tw_reuse : reuse TIME_WAIT sockets; default 0, recommended 1.
net.ipv4.tcp_tw_recycle : enable TCP TIME_WAIT recycle; default 0, recommended 1.
net.ipv4.tcp_max_syn_backlog : SYN backlog size; default 128, recommended 1024.
net.ipv4.tcp_keepalive_time : TCP keepalive interval; default 7200 s, recommended 600‑1200 s.
net.ipv4.tcp_max_tw_buckets : max TIME_WAIT sockets; default 180000, recommended 262144.
net.ipv4.ip_local_port_range : local port range; default 32768‑61000, recommended 1024‑65535.
net.ipv4.tcp_slow_start_after_idle : slow start after idle; default 1, recommended 0.
net.ipv4.tcp_no_metrics_save : save TCP metrics; default 0, recommended 1.
net.ipv4.tcp_mtu_probing : enable MTU probing; default 0, recommended 1.
net.ipv4.tcp_congestion_control : TCP congestion algorithm; default cubic, recommended bbr.
fs.file-max : max file handles; default 65536, recommended 1048576.
fs.nr_open : max open files; default 1048576, recommended 1048576.
fs.inotify.max_user_watches : max inotify watches; default 8192, recommended 524288.
kernel.sem : semaphore limits; default 250, recommended 512‑1024.
kernel.shmmax : max shared memory segment size; default 4294967295, recommended 536870912.
kernel.shmall : total shared memory pages; default 2097152, recommended 134217728.
kernel.pid_max : max PID value; default 32768, recommended 524288.
kernel.core_pattern : core dump filename pattern; default "core", recommended "/corefiles/core-%e-%s-%u-%g-%p-%t".
kernel.msgmnb : max message queue size; default 16384, recommended 65536.
kernel.msgmax : max message size; default 8192, recommended 65536.
kernel.sysrq : enable SysRq key; default 1, recommended 0.
kernel.printk : kernel log level; default "4 4 1 7", recommended "3 3 3 3".
kernel.randomize_va_space : address space randomization; default 2, recommended 2.
kernel.nmi_watchdog : NMI watchdog; default 1, recommended 0.
kernel.softlockup_panic : panic on soft lockup; default 0, recommended 1.
kernel.hung_task_panic : panic on hung task; default 0, recommended 1.
kernel.panic : panic timeout; default 0, recommended 10.
kernel.panic_on_oops : panic on Oops; default 0, recommended 1.
kernel.exec-shield : exec shield; default 1, recommended 1.
kernel.dmesg_restrict : restrict dmesg access; default 1, recommended 1.
Link: https://www.cnblogs.com/yaoqingzhuan/p/17507916.html
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