linux系統調優

kernel.sched_child_runs_first = 0
kernel.sched_min_granularity_ns = 3000000
kernel.sched_latency_ns = 15000000
kernel.sched_wakeup_granularity_ns = 3000000
kernel.sched_tunable_scaling = 1
kernel.sched_features = 3183
kernel.sched_migration_cost = 500000
kernel.sched_nr_migrate = 32
kernel.sched_time_avg = 1000
kernel.sched_shares_window = 10000000
kernel.timer_migration = 1
kernel.sched_rt_period_us = 1000000
kernel.sched_rt_runtime_us = 950000
kernel.sched_compat_yield = 0
kernel.sched_rr_timeslice_ms = 100
kernel.sched_autogroup_enabled = 0
kernel.sched_cfs_bandwidth_slice_us = 5000
kernel.panic = 0
kernel.exec-shield = 1
kernel.core_uses_pid = 1
kernel.core_pattern = core
kernel.core_pipe_limit = 0
kernel.tainted = 0
kernel.real-root-dev = 0
kernel.print-fatal-signals = 0
kernel.ctrl-alt-del = 0
kernel.ftrace_enabled = 1
kernel.stack_tracer_enabled = 0
kernel.ftrace_dump_on_oops = 0
kernel.modprobe = /sbin/modprobe
kernel.modules_disabled = 0
kernel.kexec_load_disabled = 0
kernel.hotplug = 
kernel.acct = 4    2    30
kernel.sysrq = 0
kernel.cad_pid = 1
kernel.threads-max = 62803
kernel.random.poolsize = 4096
kernel.random.entropy_avail = 168
kernel.random.read_wakeup_threshold = 64
kernel.random.write_wakeup_threshold = 128
kernel.random.boot_id = 3b7f0235-9995-4885-91ce-ea8f614896ac
kernel.random.uuid = 349859da-0492-4b69-aaba-eef98ad0a663
kernel.usermodehelper.bset = 4294967295    4294967295
kernel.usermodehelper.inheritable = 4294967295    4294967295
kernel.overflowuid = 65534
kernel.overflowgid = 65534
kernel.pid_max = 32768
kernel.panic_on_oops = 1
kernel.printk = 4    4    1    7
kernel.printk_ratelimit = 5
kernel.printk_ratelimit_burst = 10
kernel.printk_delay = 0
kernel.dmesg_restrict = 0
kernel.kptr_restrict = 1
kernel.ngroups_max = 65536
kernel.cap_last_cap = 33
kernel.watchdog = 1
kernel.watchdog_thresh = 60
kernel.softlockup_panic = 0
kernel.softlockup_all_cpu_backtrace = 0
kernel.nmi_watchdog = 1
kernel.unknown_nmi_panic = 0
kernel.panic_on_unrecovered_nmi = 0
kernel.panic_on_io_nmi = 0
kernel.bootloader_type = 113
kernel.bootloader_version = 1
kernel.kstack_depth_to_print = 12
kernel.io_delay_type = 0
kernel.randomize_va_space = 2
kernel.acpi_video_flags = 0
kernel.hung_task_panic = 0
kernel.hung_task_check_count = 4194304
kernel.hung_task_timeout_secs = 120
kernel.hung_task_warnings = 10
kernel.compat-log = 1
kernel.max_lock_depth = 1024
kernel.poweroff_cmd = /sbin/poweroff
kernel.keys.maxkeys = 200
kernel.keys.maxbytes = 20000
kernel.keys.root_maxkeys = 1000000
kernel.keys.root_maxbytes = 25000000
kernel.keys.gc_delay = 300
kernel.slow-work.min-threads = 2
kernel.slow-work.max-threads = 4
kernel.slow-work.vslow-percentage = 50
kernel.perf_event_paranoid = 1
kernel.perf_event_mlock_kb = 516
kernel.perf_event_max_sample_rate = 100000
kernel.blk_iopoll = 1
kernel.panic_on_warn = 0
kernel.sched_domain.cpu0.domain0.min_interval = 1
kernel.sched_domain.cpu0.domain0.max_interval = 4
kernel.sched_domain.cpu0.domain0.busy_idx = 2
kernel.sched_domain.cpu0.domain0.idle_idx = 0
kernel.sched_domain.cpu0.domain0.newidle_idx = 0
kernel.sched_domain.cpu0.domain0.wake_idx = 0
kernel.sched_domain.cpu0.domain0.forkexec_idx = 0
kernel.sched_domain.cpu0.domain0.busy_factor = 64
kernel.sched_domain.cpu0.domain0.imbalance_pct = 125
kernel.sched_domain.cpu0.domain0.cache_nice_tries = 1
kernel.sched_domain.cpu0.domain0.flags = 4655
kernel.sched_domain.cpu0.domain0.name = MC
kernel.sched_domain.cpu1.domain0.min_interval = 1
kernel.sched_domain.cpu1.domain0.max_interval = 4
kernel.sched_domain.cpu1.domain0.busy_idx = 2
kernel.sched_domain.cpu1.domain0.idle_idx = 0
kernel.sched_domain.cpu1.domain0.newidle_idx = 0
kernel.sched_domain.cpu1.domain0.wake_idx = 0
kernel.sched_domain.cpu1.domain0.forkexec_idx = 0
kernel.sched_domain.cpu1.domain0.busy_factor = 64
kernel.sched_domain.cpu1.domain0.imbalance_pct = 125
kernel.sched_domain.cpu1.domain0.cache_nice_tries = 1
kernel.sched_domain.cpu1.domain0.flags = 4655
kernel.sched_domain.cpu1.domain0.name = MC
kernel.sched_domain.cpu2.domain0.min_interval = 1
kernel.sched_domain.cpu2.domain0.max_interval = 4
kernel.sched_domain.cpu2.domain0.busy_idx = 2
kernel.sched_domain.cpu2.domain0.idle_idx = 0
kernel.sched_domain.cpu2.domain0.newidle_idx = 0
kernel.sched_domain.cpu2.domain0.wake_idx = 0
kernel.sched_domain.cpu2.domain0.forkexec_idx = 0
kernel.sched_domain.cpu2.domain0.busy_factor = 64
kernel.sched_domain.cpu2.domain0.imbalance_pct = 125
kernel.sched_domain.cpu2.domain0.cache_nice_tries = 1
kernel.sched_domain.cpu2.domain0.flags = 4655
kernel.sched_domain.cpu2.domain0.name = MC
kernel.sched_domain.cpu3.domain0.min_interval = 1
kernel.sched_domain.cpu3.domain0.max_interval = 4
kernel.sched_domain.cpu3.domain0.busy_idx = 2
kernel.sched_domain.cpu3.domain0.idle_idx = 0
kernel.sched_domain.cpu3.domain0.newidle_idx = 0
kernel.sched_domain.cpu3.domain0.wake_idx = 0
kernel.sched_domain.cpu3.domain0.forkexec_idx = 0
kernel.sched_domain.cpu3.domain0.busy_factor = 64
kernel.sched_domain.cpu3.domain0.imbalance_pct = 125
kernel.sched_domain.cpu3.domain0.cache_nice_tries = 1
kernel.sched_domain.cpu3.domain0.flags = 4655
kernel.sched_domain.cpu3.domain0.name = MC
kernel.vsyscall64 = 1
kernel.ostype = Linux
kernel.osrelease = 2.6.32-573.22.1.el6.x86_64
kernel.version = #1 SMP Wed Mar 23 03:35:39 UTC 2016
kernel.hostname = ap-uce-uop-mq
kernel.domainname = (none)
kernel.pty.max = 4096
kernel.pty.nr = 1
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
kernel.shmmni = 4096
kernel.shm_rmid_forced = 0
kernel.msgmax = 65536
kernel.msgmni = 15737
kernel.msgmnb = 65536
kernel.sem = 250    32000    32    128
kernel.auto_msgmni = 1
vm.overcommit_memory = 0
vm.panic_on_oom = 0
vm.oom_kill_allocating_task = 0
vm.extfrag_threshold = 500
vm.oom_dump_tasks = 1
vm.would_have_oomkilled = 0
vm.overcommit_ratio = 50
vm.overcommit_kbytes = 0
vm.page-cluster = 3
vm.dirty_background_ratio = 10
vm.dirty_background_bytes = 0
vm.dirty_ratio = 20
vm.dirty_bytes = 0
vm.dirty_writeback_centisecs = 500
vm.dirty_expire_centisecs = 3000
vm.nr_pdflush_threads = 0
vm.swappiness = 0
vm.nr_hugepages = 0
vm.nr_hugepages_mempolicy = 0
vm.hugetlb_shm_group = 0
vm.hugepages_treat_as_movable = 0
vm.nr_overcommit_hugepages = 0
vm.lowmem_reserve_ratio = 256    256    32
vm.drop_caches = 0
vm.min_free_kbytes = 67584
vm.extra_free_kbytes = 0
vm.unmap_area_factor = 0
vm.meminfo_legacy_layout = 1
vm.percpu_pagelist_fraction = 0
vm.max_map_count = 65530
vm.laptop_mode = 0
vm.block_dump = 0
vm.vfs_cache_pressure = 100
vm.legacy_va_layout = 0
vm.zone_reclaim_mode = 0
vm.min_unmapped_ratio = 1
vm.min_slab_ratio = 5
vm.stat_interval = 1
vm.mmap_min_addr = 4096
vm.numa_zonelist_order = default
vm.scan_unevictable_pages = 0
vm.memory_failure_early_kill = 0
vm.memory_failure_recovery = 1
vm.admin_reserve_kbytes = 8192
fs.inode-nr = 43147    2072
fs.inode-state = 43147    2072    0    0    0    0    0
fs.file-nr = 736    0    798336
fs.file-max = 798336
fs.nr_open = 1048576
fs.dentry-state = 43591    37426    45    0    0    0
fs.overflowuid = 65534
fs.overflowgid = 65534
fs.leases-enable = 1
fs.dir-notify-enable = 1
fs.lease-break-time = 45
fs.aio-nr = 0
fs.aio-max-nr = 65536
fs.inotify.max_user_instances = 128
fs.inotify.max_user_watches = 8192
fs.inotify.max_queued_events = 16384
fs.epoll.max_user_watches = 1646346
fs.suid_dumpable = 0
fs.binfmt_misc.status = enabled
fs.quota.lookups = 0
fs.quota.drops = 0
fs.quota.reads = 0
fs.quota.writes = 0
fs.quota.cache_hits = 0
fs.quota.allocated_dquots = 0
fs.quota.free_dquots = 0
fs.quota.syncs = 2
fs.quota.warnings = 1
fs.mqueue.queues_max = 256
fs.mqueue.msg_max = 10
fs.mqueue.msgsize_max = 8192
fs.mqueue.msg_default = 10
fs.mqueue.msgsize_default = 8192
fs.nfs.nlm_grace_period = 0
fs.nfs.nlm_timeout = 10
fs.nfs.nlm_udpport = 0
fs.nfs.nlm_tcpport = 0
fs.nfs.nsm_use_hostnames = 0
fs.nfs.nsm_local_state = 0
fs.nfs.nfs_callback_tcpport = 0
fs.nfs.idmap_cache_timeout = 600
fs.nfs.nfs_mountpoint_timeout = 500
fs.nfs.nfs_congestion_kb = 90816
debug.exception-trace = 1
debug.kprobes-optimization = 1
dev.scsi.logging_level = 0
dev.raid.speed_limit_min = 1000
dev.raid.speed_limit_max = 200000
dev.hpet.max-user-freq = 64
dev.mac_hid.mouse_button_emulation = 0
dev.mac_hid.mouse_button2_keycode = 97
dev.mac_hid.mouse_button3_keycode = 100
dev.cdrom.info = CD-ROM information, Id: cdrom.c 3.20 2003/12/17
dev.cdrom.info = 
dev.cdrom.info = drive name:        sr0
dev.cdrom.info = drive speed:        4
dev.cdrom.info = drive # of slots:    1
dev.cdrom.info = Can close tray:        1
dev.cdrom.info = Can open tray:        1
dev.cdrom.info = Can lock tray:        1
dev.cdrom.info = Can change speed:    1
dev.cdrom.info = Can select disk:    0
dev.cdrom.info = Can read multisession:    1
dev.cdrom.info = Can read MCN:        1
dev.cdrom.info = Reports media changed:    1
dev.cdrom.info = Can play audio:        1
dev.cdrom.info = Can write CD-R:        0
dev.cdrom.info = Can write CD-RW:    0
dev.cdrom.info = Can read DVD:        1
dev.cdrom.info = Can write DVD-R:    0
dev.cdrom.info = Can write DVD-RAM:    0
dev.cdrom.info = Can read MRW:        1
dev.cdrom.info = Can write MRW:        1
dev.cdrom.info = Can write RAM:        1
dev.cdrom.info = 
dev.cdrom.info = 
dev.cdrom.autoclose = 1
dev.cdrom.autoeject = 0
dev.cdrom.debug = 0
dev.cdrom.lock = 1
dev.cdrom.check_media = 0
net.netfilter.nf_log.0 = NONE
net.netfilter.nf_log.1 = NONE
net.netfilter.nf_log.2 = NONE
net.netfilter.nf_log.3 = NONE
net.netfilter.nf_log.4 = NONE
net.netfilter.nf_log.5 = NONE
net.netfilter.nf_log.6 = NONE
net.netfilter.nf_log.7 = NONE
net.netfilter.nf_log.8 = NONE
net.netfilter.nf_log.9 = NONE
net.netfilter.nf_log.10 = NONE
net.netfilter.nf_log.11 = NONE
net.netfilter.nf_log.12 = NONE
net.core.somaxconn = 128
net.core.xfrm_aevent_etime = 10
net.core.xfrm_aevent_rseqth = 2
net.core.xfrm_larval_drop = 1
net.core.xfrm_acq_expires = 30
net.core.wmem_max = 124928
net.core.rmem_max = 124928
net.core.wmem_default = 124928
net.core.rmem_default = 124928
net.core.dev_weight = 64
net.core.netdev_max_backlog = 1000
net.core.netdev_rss_key = 00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00
net.core.message_cost = 5
net.core.message_burst = 10
net.core.optmem_max = 20480
net.core.rps_sock_flow_entries = 0
net.core.busy_poll = 0
net.core.busy_read = 0
net.core.netdev_budget = 300
net.core.warnings = 1
net.ipv4.route.gc_thresh = 262144
net.ipv4.route.max_size = 4194304
net.ipv4.route.gc_min_interval = 0
net.ipv4.route.gc_min_interval_ms = 500
net.ipv4.route.gc_timeout = 300
net.ipv4.route.gc_interval = 60
net.ipv4.route.redirect_load = 20
net.ipv4.route.redirect_number = 9
net.ipv4.route.redirect_silence = 20480
net.ipv4.route.error_cost = 1000
net.ipv4.route.error_burst = 5000
net.ipv4.route.gc_elasticity = 8
net.ipv4.route.mtu_expires = 600
net.ipv4.route.min_pmtu = 552
net.ipv4.route.min_adv_mss = 256
net.ipv4.route.secret_interval = 600
net.ipv4.neigh.default.mcast_solicit = 3
net.ipv4.neigh.default.ucast_solicit = 3
net.ipv4.neigh.default.app_solicit = 0
net.ipv4.neigh.default.retrans_time = 99
net.ipv4.neigh.default.base_reachable_time = 30
net.ipv4.neigh.default.delay_first_probe_time = 5
net.ipv4.neigh.default.gc_stale_time = 120
net.ipv4.neigh.default.unres_qlen = 3
net.ipv4.neigh.default.proxy_qlen = 64
net.ipv4.neigh.default.anycast_delay = 99
net.ipv4.neigh.default.proxy_delay = 79
net.ipv4.neigh.default.locktime = 99
net.ipv4.neigh.default.retrans_time_ms = 1000
net.ipv4.neigh.default.base_reachable_time_ms = 30000
net.ipv4.neigh.default.gc_interval = 30
net.ipv4.neigh.default.gc_thresh1 = 128
net.ipv4.neigh.default.gc_thresh2 = 512
net.ipv4.neigh.default.gc_thresh3 = 1024
net.ipv4.neigh.lo.mcast_solicit = 3
net.ipv4.neigh.lo.ucast_solicit = 3
net.ipv4.neigh.lo.app_solicit = 0
net.ipv4.neigh.lo.retrans_time = 99
net.ipv4.neigh.lo.base_reachable_time = 30
net.ipv4.neigh.lo.delay_first_probe_time = 5
net.ipv4.neigh.lo.gc_stale_time = 60
net.ipv4.neigh.lo.unres_qlen = 3
net.ipv4.neigh.lo.proxy_qlen = 64
net.ipv4.neigh.lo.anycast_delay = 99
net.ipv4.neigh.lo.proxy_delay = 79
net.ipv4.neigh.lo.locktime = 99
net.ipv4.neigh.lo.retrans_time_ms = 1000
net.ipv4.neigh.lo.base_reachable_time_ms = 30000
net.ipv4.neigh.eth0.mcast_solicit = 3
net.ipv4.neigh.eth0.ucast_solicit = 3
net.ipv4.neigh.eth0.app_solicit = 0
net.ipv4.neigh.eth0.retrans_time = 99
net.ipv4.neigh.eth0.base_reachable_time = 30
net.ipv4.neigh.eth0.delay_first_probe_time = 5
net.ipv4.neigh.eth0.gc_stale_time = 120
net.ipv4.neigh.eth0.unres_qlen = 3
net.ipv4.neigh.eth0.proxy_qlen = 64
net.ipv4.neigh.eth0.anycast_delay = 99
net.ipv4.neigh.eth0.proxy_delay = 79
net.ipv4.neigh.eth0.locktime = 99
net.ipv4.neigh.eth0.retrans_time_ms = 1000
net.ipv4.neigh.eth0.base_reachable_time_ms = 30000
net.ipv4.tcp_timestamps = 1
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_sack = 1
net.ipv4.tcp_retrans_collapse = 1
net.ipv4.ip_default_ttl = 64
net.ipv4.ip_nonlocal_bind = 0
net.ipv4.tcp_syn_retries = 5
net.ipv4.tcp_synack_retries = 2
net.ipv4.tcp_max_orphans = 262144
net.ipv4.tcp_max_tw_buckets = 5000
net.ipv4.ip_dynaddr = 0
net.ipv4.tcp_keepalive_time = 7200
net.ipv4.tcp_keepalive_probes = 9
net.ipv4.tcp_keepalive_intvl = 75
net.ipv4.tcp_retries1 = 3
net.ipv4.tcp_retries2 = 15
net.ipv4.tcp_fin_timeout = 60
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_tw_recycle = 0
net.ipv4.tcp_abort_on_overflow = 0
net.ipv4.tcp_stdurg = 0
net.ipv4.tcp_rfc1337 = 0
net.ipv4.tcp_max_syn_backlog = 1024
net.ipv4.ip_local_port_range = 32768    61000
net.ipv4.ip_local_reserved_ports = 
net.ipv4.igmp_max_memberships = 20
net.ipv4.igmp_max_msf = 10
net.ipv4.inet_peer_threshold = 65664
net.ipv4.inet_peer_minttl = 120
net.ipv4.inet_peer_maxttl = 600
net.ipv4.inet_peer_gc_mintime = 10
net.ipv4.inet_peer_gc_maxtime = 120
net.ipv4.tcp_orphan_retries = 0
net.ipv4.tcp_fack = 1
net.ipv4.tcp_reordering = 3
net.ipv4.tcp_ecn = 2
net.ipv4.tcp_dsack = 1
net.ipv4.tcp_mem = 753600    1004800    1507200
net.ipv4.tcp_wmem = 4096    16384    4194304
net.ipv4.tcp_rmem = 4096    87380    4194304
net.ipv4.tcp_app_win = 31
net.ipv4.tcp_adv_win_scale = 2
net.ipv4.tcp_tw_reuse = 0
net.ipv4.tcp_frto = 2
net.ipv4.tcp_frto_response = 0
net.ipv4.tcp_low_latency = 0
net.ipv4.tcp_no_metrics_save = 0
net.ipv4.tcp_moderate_rcvbuf = 1
net.ipv4.tcp_tso_win_divisor = 3
net.ipv4.tcp_congestion_control = cubic
net.ipv4.tcp_abc = 0
net.ipv4.tcp_mtu_probing = 0
net.ipv4.tcp_base_mss = 512
net.ipv4.tcp_workaround_signed_windows = 0
net.ipv4.tcp_challenge_ack_limit = 100
net.ipv4.tcp_limit_output_bytes = 262144
net.ipv4.tcp_dma_copybreak = 4096
net.ipv4.tcp_slow_start_after_idle = 1
net.ipv4.cipso_cache_enable = 1
net.ipv4.cipso_cache_bucket_size = 10
net.ipv4.cipso_rbm_optfmt = 0
net.ipv4.cipso_rbm_strictvalid = 1
net.ipv4.tcp_available_congestion_control = cubic reno
net.ipv4.tcp_allowed_congestion_control = cubic reno
net.ipv4.tcp_max_ssthresh = 0
net.ipv4.tcp_thin_linear_timeouts = 0
net.ipv4.tcp_thin_dupack = 0
net.ipv4.tcp_min_tso_segs = 2
net.ipv4.udp_mem = 753600    1004800    1507200
net.ipv4.udp_rmem_min = 4096
net.ipv4.udp_wmem_min = 4096
net.ipv4.conf.all.forwarding = 0
net.ipv4.conf.all.mc_forwarding = 0
net.ipv4.conf.all.accept_redirects = 1
net.ipv4.conf.all.secure_redirects = 1
net.ipv4.conf.all.shared_media = 1
net.ipv4.conf.all.rp_filter = 0
net.ipv4.conf.all.send_redirects = 1
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.all.src_valid_mark = 0
net.ipv4.conf.all.proxy_arp = 0
net.ipv4.conf.all.medium_id = 0
net.ipv4.conf.all.bootp_relay = 0
net.ipv4.conf.all.log_martians = 0
net.ipv4.conf.all.tag = 0
net.ipv4.conf.all.arp_filter = 0
net.ipv4.conf.all.arp_announce = 2
net.ipv4.conf.all.arp_ignore = 0
net.ipv4.conf.all.arp_accept = 0
net.ipv4.conf.all.arp_notify = 0
net.ipv4.conf.all.proxy_arp_pvlan = 0
net.ipv4.conf.all.disable_xfrm = 0
net.ipv4.conf.all.disable_policy = 0
net.ipv4.conf.all.force_igmp_version = 0
net.ipv4.conf.all.promote_secondaries = 0
net.ipv4.conf.all.accept_local = 0
net.ipv4.conf.all.route_localnet = 0
net.ipv4.conf.default.forwarding = 0
net.ipv4.conf.default.mc_forwarding = 0
net.ipv4.conf.default.accept_redirects = 1
net.ipv4.conf.default.secure_redirects = 1
net.ipv4.conf.default.shared_media = 1
net.ipv4.conf.default.rp_filter = 0
net.ipv4.conf.default.send_redirects = 1
net.ipv4.conf.default.accept_source_route = 0
net.ipv4.conf.default.src_valid_mark = 0
net.ipv4.conf.default.proxy_arp = 0
net.ipv4.conf.default.medium_id = 0
net.ipv4.conf.default.bootp_relay = 0
net.ipv4.conf.default.log_martians = 0
net.ipv4.conf.default.tag = 0
net.ipv4.conf.default.arp_filter = 0
net.ipv4.conf.default.arp_announce = 2
net.ipv4.conf.default.arp_ignore = 0
net.ipv4.conf.default.arp_accept = 0
net.ipv4.conf.default.arp_notify = 0
net.ipv4.conf.default.proxy_arp_pvlan = 0
net.ipv4.conf.default.disable_xfrm = 0
net.ipv4.conf.default.disable_policy = 0
net.ipv4.conf.default.force_igmp_version = 0
net.ipv4.conf.default.promote_secondaries = 0
net.ipv4.conf.default.accept_local = 0
net.ipv4.conf.default.route_localnet = 0
net.ipv4.conf.lo.forwarding = 0
net.ipv4.conf.lo.mc_forwarding = 0
net.ipv4.conf.lo.accept_redirects = 1
net.ipv4.conf.lo.secure_redirects = 1
net.ipv4.conf.lo.shared_media = 1
net.ipv4.conf.lo.rp_filter = 0
net.ipv4.conf.lo.send_redirects = 1
net.ipv4.conf.lo.accept_source_route = 1
net.ipv4.conf.lo.src_valid_mark = 0
net.ipv4.conf.lo.proxy_arp = 0
net.ipv4.conf.lo.medium_id = 0
net.ipv4.conf.lo.bootp_relay = 0
net.ipv4.conf.lo.log_martians = 0
net.ipv4.conf.lo.tag = 0
net.ipv4.conf.lo.arp_filter = 0
net.ipv4.conf.lo.arp_announce = 2
net.ipv4.conf.lo.arp_ignore = 0
net.ipv4.conf.lo.arp_accept = 0
net.ipv4.conf.lo.arp_notify = 0
net.ipv4.conf.lo.proxy_arp_pvlan = 0
net.ipv4.conf.lo.disable_xfrm = 1
net.ipv4.conf.lo.disable_policy = 1
net.ipv4.conf.lo.force_igmp_version = 0
net.ipv4.conf.lo.promote_secondaries = 0
net.ipv4.conf.lo.accept_local = 0
net.ipv4.conf.lo.route_localnet = 0
net.ipv4.conf.eth0.forwarding = 0
net.ipv4.conf.eth0.mc_forwarding = 0
net.ipv4.conf.eth0.accept_redirects = 1
net.ipv4.conf.eth0.secure_redirects = 1
net.ipv4.conf.eth0.shared_media = 1
net.ipv4.conf.eth0.rp_filter = 0
net.ipv4.conf.eth0.send_redirects = 1
net.ipv4.conf.eth0.accept_source_route = 0
net.ipv4.conf.eth0.src_valid_mark = 0
net.ipv4.conf.eth0.proxy_arp = 0
net.ipv4.conf.eth0.medium_id = 0
net.ipv4.conf.eth0.bootp_relay = 0
net.ipv4.conf.eth0.log_martians = 0
net.ipv4.conf.eth0.tag = 0
net.ipv4.conf.eth0.arp_filter = 0
net.ipv4.conf.eth0.arp_announce = 2
net.ipv4.conf.eth0.arp_ignore = 0
net.ipv4.conf.eth0.arp_accept = 0
net.ipv4.conf.eth0.arp_notify = 0
net.ipv4.conf.eth0.proxy_arp_pvlan = 0
net.ipv4.conf.eth0.disable_xfrm = 0
net.ipv4.conf.eth0.disable_policy = 0
net.ipv4.conf.eth0.force_igmp_version = 0
net.ipv4.conf.eth0.promote_secondaries = 0
net.ipv4.conf.eth0.accept_local = 0
net.ipv4.conf.eth0.route_localnet = 0
net.ipv4.ip_forward = 0
net.ipv4.xfrm4_gc_thresh = 2097152
net.ipv4.ipfrag_high_thresh = 4194304
net.ipv4.ipfrag_low_thresh = 3145728
net.ipv4.ipfrag_time = 30
net.ipv4.icmp_echo_ignore_all = 0
net.ipv4.icmp_echo_ignore_broadcasts = 1
net.ipv4.icmp_ignore_bogus_error_responses = 1
net.ipv4.icmp_errors_use_inbound_ifaddr = 0
net.ipv4.icmp_ratelimit = 1000
net.ipv4.icmp_ratemask = 6168
net.ipv4.rt_cache_rebuild_count = 4
net.ipv4.ping_group_range = 1    0
net.ipv4.ip_no_pmtu_disc = 0
net.ipv4.ip_forward_use_pmtu = 0
net.ipv4.ipfrag_secret_interval = 600
net.ipv4.ipfrag_max_dist = 64
net.unix.max_dgram_qlen = 10
abi.vsyscall32 = 1
crypto.fips_enabled = 0
sunrpc.rpc_debug = 0
sunrpc.nfs_debug = 0
sunrpc.nfsd_debug = 0
sunrpc.nlm_debug = 0
sunrpc.transports = tcp 1048576
sunrpc.transports = udp 32768
sunrpc.transports = tcp-bc 1048576
sunrpc.udp_slot_table_entries = 16
sunrpc.tcp_slot_table_entries = 2
sunrpc.tcp_max_slot_table_entries = 65536
sunrpc.min_resvport = 665
sunrpc.max_resvport = 1023
sunrpc.tcp_fin_timeout = 15

阿里雲內核參數

 kernel.sched_child_runs_first = 0
sysctl_sched_child_runs_first，該變量表示在建立子進程的時候是否讓子進程搶佔父進程，即便父進程的vruntime小於子進程，這個會減小公平性，可是能夠下降write_on_copy，具體要根據系統的應用狀況來考量使用哪一種方式（見task_fork_fair過程）

kernel.sched_min_granularity_ns = 3000000
（4000000ns）：sysctl_sched_min_granularity，表示進程最少運行時間，防止頻繁的切換，對於交互系統（如桌面），該值能夠設置得較小，這樣能夠保證交互獲得更快的響應（見週期調度器的check_preempt_tick過程）

kernel.sched_latency_ns = 15000000
sysctl_sched_latency，表示一個運行隊列全部進程運行一次的週期，當前這個與運行隊列的進程數有關，若是進程數超過sched_nr_latency（這個變量不能經過/proc設置，它是由(sysctl_sched_latency+ sysctl_sched_min_granularity-1)/sysctl_sched_min_granularity肯定的），那麼調度週期就是sched_min_granularity_ns*運行隊列裏的進程數，與sysctl_sched_latency無關；不然隊列進程數小於sched_nr_latency，運行週期就是sysctl_sched_latency。顯然這個數越小，一個運行隊列支持的sched_nr_latency越少，並且當sysctl_sched_min_granularity越小時能支持的sched_nr_latency越多，那麼每一個進程在這個週期內能執行的時間也就越少，這也與上面sysctl_sched_min_granularity變量的討論一致。其實sched_nr_latency也能夠當作咱們cpu load的基準值，若是cpu的load大於這個值，那麼說明cpu不夠使用了

kernel.sched_wakeup_granularity_ns = 3000000
sysctl_sched_wakeup_granularity，該變量表示進程被喚醒後至少應該運行的時間的基數，它只是用來判斷某個進程是否應該搶佔當前進程，並不表明它可以執行的最小時間（sysctl_sched_min_granularity），若是這個數值越小，那麼發生搶佔的機率也就越高（見wakeup_gran、wakeup_preempt_entity函數）

kernel.sched_tunable_scaling = 1
sysctl_sched_tunable_scaling，當內核試圖調整sched_min_granularity，sched_latency和sched_wakeup_granularity這三個值的時候所使用的更新方法，0爲不調整，1爲按照cpu個數以2爲底的對數值進行調整，2爲按照cpu的個數進行線性比例的調整

kernel.sched_features = 3183
sysctl_sched_features，該變量表示調度器支持的特性，如GENTLE_FAIR_SLEEPERS(平滑的補償睡眠進程),START_DEBIT(新進程儘可能的早調度),WAKEUP_PREEMPT(是否wakeup的進程能夠去搶佔當前運行的進程)等，全部的features見內核sech_features.h文件的定義

kernel.sched_migration_cost = 500000
sysctl_sched_migration_cost該變量用來判斷一個進程是否仍是hot，若是進程的運行時間（now - p->se.exec_start）小於它，那麼內核認爲它的code還在cache裏，因此該進程仍是hot，那麼在遷移的時候就不會考慮它

kernel.sched_nr_migrate = 32
sysctl_sched_nr_migrate，在多CPU狀況下進行負載均衡時，一次最多移動多少個進程到另外一個CPU上

kernel.sched_time_avg = 1000
kernel.sched_shares_window = 10000000
kernel.timer_migration = 1
kernel.sched_rt_period_us = 1000000
該參數與sched_rt_runtime_us一塊兒決定了實時進程在以sched_rt_period爲週期的時間內，實時進程最多可以運行的總的時間不能超過sched_rt_runtime_us

kernel.sched_rt_runtime_us = 950000
該參數與sched_rt_period一塊兒決定了實時進程在以sched_rt_period爲週期的時間內，實時進程最多可以運行的總的時間不能超過sched_rt_runtime_us

kernel.sched_compat_yield = 0

kernel.sched_rr_timeslice_ms = 100
用來指示round robin調度進程的間隔，這個間隔默認是100ms
kernel.sched_autogroup_enabled = 0
啓用後，內核會建立任務組來優化桌面程序的調度。它將把佔用大量資源的應用程序放在它們本身的任務組，這有助於性能提高
0：禁止
1：開啓

kernel.sched_cfs_bandwidth_slice_us = 5000
kernel.panic = 0
kernel.exec-shield = 1
kernel.core_uses_pid = 1
kernel.core_pattern = core
kernel.core_pipe_limit = 0
kernel.tainted = 0
kernel.real-root-dev = 0
kernel.print-fatal-signals = 0
kernel.ctrl-alt-del = 0
kernel.ftrace_enabled = 1
kernel.stack_tracer_enabled = 0
kernel.ftrace_dump_on_oops = 0
kernel.modprobe = /sbin/modprobe
kernel.modules_disabled = 0
kernel.kexec_load_disabled = 0
kernel.hotplug =
kernel.acct = 4    2    30
kernel.sysrq = 0
kernel.cad_pid = 1
kernel.threads-max = 62803
kernel.random.poolsize = 4096
kernel.random.entropy_avail = 168
kernel.random.read_wakeup_threshold = 64
kernel.random.write_wakeup_threshold = 128
kernel.random.boot_id = 3b7f0235-9995-4885-91ce-ea8f614896ac
kernel.random.uuid = 349859da-0492-4b69-aaba-eef98ad0a663
kernel.usermodehelper.bset = 4294967295    4294967295
kernel.usermodehelper.inheritable = 4294967295    4294967295
kernel.overflowuid = 65534
kernel.overflowgid = 65534
kernel.pid_max = 32768
kernel.panic_on_oops = 1
kernel.printk = 4    4    1    7
kernel.printk_ratelimit = 5
kernel.printk_ratelimit_burst = 10
kernel.printk_delay = 0
kernel.dmesg_restrict = 0
kernel.kptr_restrict = 1
kernel.ngroups_max = 65536
kernel.cap_last_cap = 33
kernel.watchdog = 1
kernel.watchdog_thresh = 60
kernel.softlockup_panic = 0
設置產生softlockup時是否拋出一個panic。Softlockup用於檢測CPU能夠響應中斷，可是在長時間內不能調度（好比禁止搶佔時間太長）的死鎖狀況。這個機制運行在一個hrtimer的中斷上下文，每隔一段時間檢測一下是否發生了調度，若是過長時間沒發生調度，說明系統被死鎖。
0：不產生panic
1：產生panic

kernel.softlockup_all_cpu_backtrace = 0
kernel.nmi_watchdog = 1
使能nmi_watchdog
0：禁止
1：開啓
kernel.unknown_nmi_panic = 0
kernel.panic_on_unrecovered_nmi = 0
kernel.panic_on_io_nmi = 0
kernel.bootloader_type = 113
kernel.bootloader_version = 1
kernel.kstack_depth_to_print = 12
kernel.io_delay_type = 0
kernel.randomize_va_space = 2
kernel.acpi_video_flags = 0
kernel.hung_task_panic = 0
kernel.hung_task_check_count = 4194304
kernel.hung_task_timeout_secs = 120
kernel.hung_task_warnings = 10
kernel.compat-log = 1
kernel.max_lock_depth = 1024
kernel.poweroff_cmd = /sbin/poweroff
kernel.keys.maxkeys = 200
kernel.keys.maxbytes = 20000
kernel.keys.root_maxkeys = 1000000
kernel.keys.root_maxbytes = 25000000
kernel.keys.gc_delay = 300
kernel.slow-work.min-threads = 2
kernel.slow-work.max-threads = 4
kernel.slow-work.vslow-percentage = 50
kernel.perf_event_paranoid = 1
kernel.perf_event_mlock_kb = 516
kernel.perf_event_max_sample_rate = 100000
kernel.blk_iopoll = 1
kernel.panic_on_warn = 0
kernel.sched_domain.cpu0.domain0.min_interval = 1
kernel.sched_domain.cpu0.domain0.max_interval = 4
kernel.sched_domain.cpu0.domain0.busy_idx = 2
kernel.sched_domain.cpu0.domain0.idle_idx = 0
kernel.sched_domain.cpu0.domain0.newidle_idx = 0
kernel.sched_domain.cpu0.domain0.wake_idx = 0
kernel.sched_domain.cpu0.domain0.forkexec_idx = 0
kernel.sched_domain.cpu0.domain0.busy_factor = 64
kernel.sched_domain.cpu0.domain0.imbalance_pct = 125
kernel.sched_domain.cpu0.domain0.cache_nice_tries = 1
kernel.sched_domain.cpu0.domain0.flags = 4655
kernel.sched_domain.cpu0.domain0.name = MC
kernel.sched_domain.cpu1.domain0.min_interval = 1
kernel.sched_domain.cpu1.domain0.max_interval = 4
kernel.sched_domain.cpu1.domain0.busy_idx = 2
kernel.sched_domain.cpu1.domain0.idle_idx = 0
kernel.sched_domain.cpu1.domain0.newidle_idx = 0
kernel.sched_domain.cpu1.domain0.wake_idx = 0
kernel.sched_domain.cpu1.domain0.forkexec_idx = 0
kernel.sched_domain.cpu1.domain0.busy_factor = 64
kernel.sched_domain.cpu1.domain0.imbalance_pct = 125
kernel.sched_domain.cpu1.domain0.cache_nice_tries = 1
kernel.sched_domain.cpu1.domain0.flags = 4655
kernel.sched_domain.cpu1.domain0.name = MC
kernel.sched_domain.cpu2.domain0.min_interval = 1
kernel.sched_domain.cpu2.domain0.max_interval = 4
kernel.sched_domain.cpu2.domain0.busy_idx = 2
kernel.sched_domain.cpu2.domain0.idle_idx = 0
kernel.sched_domain.cpu2.domain0.newidle_idx = 0
kernel.sched_domain.cpu2.domain0.wake_idx = 0
kernel.sched_domain.cpu2.domain0.forkexec_idx = 0
kernel.sched_domain.cpu2.domain0.busy_factor = 64
kernel.sched_domain.cpu2.domain0.imbalance_pct = 125
kernel.sched_domain.cpu2.domain0.cache_nice_tries = 1
kernel.sched_domain.cpu2.domain0.flags = 4655
kernel.sched_domain.cpu2.domain0.name = MC
kernel.sched_domain.cpu3.domain0.min_interval = 1
kernel.sched_domain.cpu3.domain0.max_interval = 4
kernel.sched_domain.cpu3.domain0.busy_idx = 2
kernel.sched_domain.cpu3.domain0.idle_idx = 0
kernel.sched_domain.cpu3.domain0.newidle_idx = 0
kernel.sched_domain.cpu3.domain0.wake_idx = 0
kernel.sched_domain.cpu3.domain0.forkexec_idx = 0
kernel.sched_domain.cpu3.domain0.busy_factor = 64
kernel.sched_domain.cpu3.domain0.imbalance_pct = 125
kernel.sched_domain.cpu3.domain0.cache_nice_tries = 1
kernel.sched_domain.cpu3.domain0.flags = 4655
kernel.sched_domain.cpu3.domain0.name = MC
kernel.vsyscall64 = 1
kernel.ostype = Linux
kernel.osrelease = 2.6.32-573.22.1.el6.x86_64
kernel.version = #1 SMP Wed Mar 23 03:35:39 UTC 2016
kernel.hostname = ap-uce-uop-mq
kernel.domainname = (none)
kernel.pty.max = 4096
kernel.pty.nr = 1
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
kernel.shmmni = 4096
kernel.shm_rmid_forced = 0
kernel.msgmax = 65536
kernel.msgmni = 15737
kernel.msgmnb = 65536
kernel.sem = 250    32000    32    128
kernel.auto_msgmni = 1
vm.overcommit_memory = 0
vm.panic_on_oom = 0
vm.oom_kill_allocating_task = 0
vm.extfrag_threshold = 500
vm.oom_dump_tasks = 1
vm.would_have_oomkilled = 0
vm.overcommit_ratio = 50
vm.overcommit_kbytes = 0
vm.page-cluster = 3
vm.dirty_background_ratio = 10
vm.dirty_background_bytes = 0
vm.dirty_ratio = 20
vm.dirty_bytes = 0
vm.dirty_writeback_centisecs = 500
vm.dirty_expire_centisecs = 3000
vm.nr_pdflush_threads = 0
vm.swappiness = 0
vm.nr_hugepages = 0
vm.nr_hugepages_mempolicy = 0
vm.hugetlb_shm_group = 0
vm.hugepages_treat_as_movable = 0
vm.nr_overcommit_hugepages = 0
vm.lowmem_reserve_ratio = 256    256    32
vm.drop_caches = 0
vm.min_free_kbytes = 67584
vm.extra_free_kbytes = 0
vm.unmap_area_factor = 0
vm.meminfo_legacy_layout = 1
vm.percpu_pagelist_fraction = 0
vm.max_map_count = 65530
vm.laptop_mode = 0
vm.block_dump = 0
vm.vfs_cache_pressure = 100
vm.legacy_va_layout = 0
vm.zone_reclaim_mode = 0
vm.min_unmapped_ratio = 1
vm.min_slab_ratio = 5
vm.stat_interval = 1
vm.mmap_min_addr = 4096
vm.numa_zonelist_order = default
vm.scan_unevictable_pages = 0
vm.memory_failure_early_kill = 0
vm.memory_failure_recovery = 1
vm.admin_reserve_kbytes = 8192
fs.inode-nr = 43147    2072
fs.inode-state = 43147    2072    0    0    0    0    0
fs.file-nr = 736    0    798336
fs.file-max = 798336
fs.nr_open = 1048576
fs.dentry-state = 43591    37426    45    0    0    0
fs.overflowuid = 65534
fs.overflowgid = 65534
fs.leases-enable = 1
fs.dir-notify-enable = 1
fs.lease-break-time = 45
fs.aio-nr = 0
fs.aio-max-nr = 65536
fs.inotify.max_user_instances = 128
fs.inotify.max_user_watches = 8192
fs.inotify.max_queued_events = 16384
fs.epoll.max_user_watches = 1646346
fs.suid_dumpable = 0
fs.binfmt_misc.status = enabled
fs.quota.lookups = 0
fs.quota.drops = 0
fs.quota.reads = 0
fs.quota.writes = 0
fs.quota.cache_hits = 0
fs.quota.allocated_dquots = 0
fs.quota.free_dquots = 0
fs.quota.syncs = 2
fs.quota.warnings = 1
fs.mqueue.queues_max = 256
fs.mqueue.msg_max = 10
fs.mqueue.msgsize_max = 8192
fs.mqueue.msg_default = 10
fs.mqueue.msgsize_default = 8192
fs.nfs.nlm_grace_period = 0
fs.nfs.nlm_timeout = 10
fs.nfs.nlm_udpport = 0
fs.nfs.nlm_tcpport = 0
fs.nfs.nsm_use_hostnames = 0
fs.nfs.nsm_local_state = 0
fs.nfs.nfs_callback_tcpport = 0
fs.nfs.idmap_cache_timeout = 600
fs.nfs.nfs_mountpoint_timeout = 500
fs.nfs.nfs_congestion_kb = 90816
debug.exception-trace = 1
debug.kprobes-optimization = 1
dev.scsi.logging_level = 0
dev.raid.speed_limit_min = 1000
dev.raid.speed_limit_max = 200000
dev.hpet.max-user-freq = 64
dev.mac_hid.mouse_button_emulation = 0
dev.mac_hid.mouse_button2_keycode = 97
dev.mac_hid.mouse_button3_keycode = 100
dev.cdrom.info = CD-ROM information, Id: cdrom.c 3.20 2003/12/17
dev.cdrom.info =
dev.cdrom.info = drive name:        sr0
dev.cdrom.info = drive speed:        4
dev.cdrom.info = drive # of slots:    1
dev.cdrom.info = Can close tray:        1
dev.cdrom.info = Can open tray:        1
dev.cdrom.info = Can lock tray:        1
dev.cdrom.info = Can change speed:    1
dev.cdrom.info = Can select disk:    0
dev.cdrom.info = Can read multisession:    1
dev.cdrom.info = Can read MCN:        1
dev.cdrom.info = Reports media changed:    1
dev.cdrom.info = Can play audio:        1
dev.cdrom.info = Can write CD-R:        0
dev.cdrom.info = Can write CD-RW:    0
dev.cdrom.info = Can read DVD:        1
dev.cdrom.info = Can write DVD-R:    0
dev.cdrom.info = Can write DVD-RAM:    0
dev.cdrom.info = Can read MRW:        1
dev.cdrom.info = Can write MRW:        1
dev.cdrom.info = Can write RAM:        1
dev.cdrom.info =
dev.cdrom.info =
dev.cdrom.autoclose = 1
dev.cdrom.autoeject = 0
dev.cdrom.debug = 0
dev.cdrom.lock = 1
dev.cdrom.check_media = 0
net.netfilter.nf_log.0 = NONE
net.netfilter.nf_log.1 = NONE
net.netfilter.nf_log.2 = NONE
net.netfilter.nf_log.3 = NONE
net.netfilter.nf_log.4 = NONE
net.netfilter.nf_log.5 = NONE
net.netfilter.nf_log.6 = NONE
net.netfilter.nf_log.7 = NONE
net.netfilter.nf_log.8 = NONE
net.netfilter.nf_log.9 = NONE
net.netfilter.nf_log.10 = NONE
net.netfilter.nf_log.11 = NONE
net.netfilter.nf_log.12 = NONE
net.core.somaxconn = 128
net.core.xfrm_aevent_etime = 10
net.core.xfrm_aevent_rseqth = 2
net.core.xfrm_larval_drop = 1
net.core.xfrm_acq_expires = 30
net.core.wmem_max = 124928
net.core.rmem_max = 124928
net.core.wmem_default = 124928
net.core.rmem_default = 124928
net.core.dev_weight = 64
net.core.netdev_max_backlog = 1000
net.core.netdev_rss_key = 00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00
net.core.message_cost = 5
net.core.message_burst = 10
net.core.optmem_max = 20480
net.core.rps_sock_flow_entries = 0
net.core.busy_poll = 0
net.core.busy_read = 0
net.core.netdev_budget = 300
net.core.warnings = 1
net.ipv4.route.gc_thresh = 262144
net.ipv4.route.max_size = 4194304
net.ipv4.route.gc_min_interval = 0
net.ipv4.route.gc_min_interval_ms = 500
net.ipv4.route.gc_timeout = 300
net.ipv4.route.gc_interval = 60
net.ipv4.route.redirect_load = 20
net.ipv4.route.redirect_number = 9
net.ipv4.route.redirect_silence = 20480
net.ipv4.route.error_cost = 1000
net.ipv4.route.error_burst = 5000
net.ipv4.route.gc_elasticity = 8
net.ipv4.route.mtu_expires = 600
net.ipv4.route.min_pmtu = 552
net.ipv4.route.min_adv_mss = 256
net.ipv4.route.secret_interval = 600
net.ipv4.neigh.default.mcast_solicit = 3
net.ipv4.neigh.default.ucast_solicit = 3
net.ipv4.neigh.default.app_solicit = 0
net.ipv4.neigh.default.retrans_time = 99
net.ipv4.neigh.default.base_reachable_time = 30
net.ipv4.neigh.default.delay_first_probe_time = 5
net.ipv4.neigh.default.gc_stale_time = 120
net.ipv4.neigh.default.unres_qlen = 3
net.ipv4.neigh.default.proxy_qlen = 64
net.ipv4.neigh.default.anycast_delay = 99
net.ipv4.neigh.default.proxy_delay = 79
net.ipv4.neigh.default.locktime = 99
net.ipv4.neigh.default.retrans_time_ms = 1000
net.ipv4.neigh.default.base_reachable_time_ms = 30000
net.ipv4.neigh.default.gc_interval = 30
net.ipv4.neigh.default.gc_thresh1 = 128
net.ipv4.neigh.default.gc_thresh2 = 512
net.ipv4.neigh.default.gc_thresh3 = 1024
net.ipv4.neigh.lo.mcast_solicit = 3
net.ipv4.neigh.lo.ucast_solicit = 3
net.ipv4.neigh.lo.app_solicit = 0
net.ipv4.neigh.lo.retrans_time = 99
net.ipv4.neigh.lo.base_reachable_time = 30
net.ipv4.neigh.lo.delay_first_probe_time = 5
net.ipv4.neigh.lo.gc_stale_time = 60
net.ipv4.neigh.lo.unres_qlen = 3
net.ipv4.neigh.lo.proxy_qlen = 64
net.ipv4.neigh.lo.anycast_delay = 99
net.ipv4.neigh.lo.proxy_delay = 79
net.ipv4.neigh.lo.locktime = 99
net.ipv4.neigh.lo.retrans_time_ms = 1000
net.ipv4.neigh.lo.base_reachable_time_ms = 30000
net.ipv4.neigh.eth0.mcast_solicit = 3
net.ipv4.neigh.eth0.ucast_solicit = 3
net.ipv4.neigh.eth0.app_solicit = 0
net.ipv4.neigh.eth0.retrans_time = 99
net.ipv4.neigh.eth0.base_reachable_time = 30
net.ipv4.neigh.eth0.delay_first_probe_time = 5
net.ipv4.neigh.eth0.gc_stale_time = 120
net.ipv4.neigh.eth0.unres_qlen = 3
net.ipv4.neigh.eth0.proxy_qlen = 64
net.ipv4.neigh.eth0.anycast_delay = 99
net.ipv4.neigh.eth0.proxy_delay = 79
net.ipv4.neigh.eth0.locktime = 99
net.ipv4.neigh.eth0.retrans_time_ms = 1000
net.ipv4.neigh.eth0.base_reachable_time_ms = 30000
net.ipv4.tcp_timestamps = 1
缺省值爲1
Timestamps 用在其它一些東西中﹐能夠防範那些僞造的 sequence 號碼。一條1G的寬帶線路或許會重遇到帶 out-of-line數值的舊sequence 號碼(假如它是因爲上次產生的)。Timestamp 會讓它知道這是個 '舊封包'。(該文件表示是否啓用以一種比超時重發更精確的方法（RFC 1323）來啓用對 RTT 的計算；爲了實現更好的性能應該啓用這個選項。)

net.ipv4.tcp_window_scaling = 1
缺省值爲1
該文件表示設置tcp/ip會話的滑動窗口大小是否可變。參數值爲布爾值，爲1時表示可變，爲0時表示不可變。tcp/ip一般使用的窗口最大可達到 65535 字節，對於高速網絡，該值可能過小，這時候若是啓用了該功能，可使tcp/ip滑動窗口大小增大數個數量級，從而提升數據傳輸的能力(RFC 1323)。（對普通地百M網絡而言，關閉會下降開銷，因此若是不是高速網絡，能夠考慮設置爲0）

net.ipv4.tcp_sack = 1
缺省值爲1
使用 Selective ACK﹐它能夠用來查找特定的遺失的數據報--- 所以有助於快速恢復狀態。該文件表示是否啓用有選擇的應答（Selective Acknowledgment），這能夠經過有選擇地應答亂序接收到的報文來提升性能（這樣可讓發送者只發送丟失的報文段）。(對於廣域網通訊來講這個選項應該啓用，可是這會增長對 CPU 的佔用。)

net.ipv4.tcp_retrans_collapse = 1
缺省值爲1
對於某些有bug的打印機提供針對其bug的兼容性。(通常不須要這個支持,能夠關閉它)

net.ipv4.ip_default_ttl = 64
net.ipv4.ip_nonlocal_bind = 0
net.ipv4.tcp_syn_retries = 5
對於一個新建鏈接，內核要發送多少個 SYN 鏈接請求才決定放棄。不該該大於255，默認值是5，對應於180秒左右時間。(對於大負載而物理通訊良好的網絡而言,這個值偏高,可修改成2.這個值僅僅是針對對外的鏈接,對進來的鏈接,是由tcp_retries1 決定的)

net.ipv4.tcp_synack_retries = 2
對於遠端的鏈接請求SYN，內核會發送SYN ＋ ACK數據報，以確認收到上一個 SYN鏈接請求包。這是所謂的三次握手( threeway handshake)機制的第二個步驟。這裏決定內核在放棄鏈接以前所送出的 SYN+ACK 數目。不該該大於255，默認值是5，對應於180秒左右時間。(能夠根據上面的tcp_syn_retries來決定這個值)

net.ipv4.tcp_max_orphans = 262144
缺省值是8192
系統所能處理不屬於任何進程的TCP sockets最大數量。假如超過這個數量﹐那麼不屬於任何進程的鏈接會被當即reset，並同時顯示警告信息。之因此要設定這個限制﹐純粹爲了抵禦那些簡單的 DoS 攻擊﹐千萬不要依賴這個或是人爲的下降這個限制(這個值Redhat AS版本中設置爲32768,可是不少防火牆修改的時候,建議該值修改成2000)

net.ipv4.tcp_max_tw_buckets = 5000
默認值是180000
系統在同時所處理的最大 timewait sockets 數目。若是超過此數的話﹐time-wait socket 會被當即砍除而且顯示警告信息。之因此要設定這個限制﹐純粹爲了抵禦那些簡單的 DoS 攻擊﹐千萬不要人爲的下降這個限制﹐不過﹐若是網絡條件須要比默認值更多﹐則能夠提升它(或許還要增長內存)。(事實上作NAT的時候最好能夠適當地增長該值)

net.ipv4.ip_dynaddr = 0
net.ipv4.tcp_keepalive_time = 7200
當keepalive打開的狀況下，TCP發送keepalive消息的頻率。(因爲目前網絡攻擊等因素,形成了利用這個進行的攻擊很頻繁,曾經也有cu的朋友提到過,說若是2邊創建了鏈接,而後不發送任何數據或者rst/fin消息,那麼持續的時間是否是就是2小時,空鏈接攻擊?tcp_keepalive_time就是預防此情形的.我我的在作nat服務的時候的修改值爲1800秒)

net.ipv4.tcp_keepalive_probes = 9
TCP發送keepalive探測以肯定該鏈接已經斷開的次數。(注意:保持鏈接僅在SO_KEEPALIVE套接字選項被打開是才發送.次數默認不須要修改,固然根據情形也能夠適當地縮短此值.設置爲5比較合適)

net.ipv4.tcp_keepalive_intvl = 75
探測消息發送的頻率，乘以tcp_keepalive_probes就獲得對於從開始探測以來沒有響應的鏈接殺除的時間。默認值爲75秒，也就是沒有活動的鏈接將在大約11分鐘之後將被丟棄。(對於普通應用來講,這個值有一些偏大,能夠根據須要改小.特別是web類服務器須要改小該值,15是個比較合適的值)

net.ipv4.tcp_retries1 = 3
放棄迴應一個TCP鏈接請求前﹐須要進行多少次重試。RFC 規定最低的數值是3﹐這也是默認值﹐根據RTO的值大約在3秒 - 8分鐘之間。(注意:這個值同時還決定進入的syn鏈接)

net.ipv4.tcp_retries2 = 15
在丟棄激活(已創建通信情況)的TCP鏈接以前﹐須要進行多少次重試。默認值爲15，根據RTO的值來決定，至關於13-30分鐘(RFC1122規定，必須大於100秒).(這個值根據目前的網絡設置,能夠適當地改小,個人網絡內修改成了5)

net.ipv4.tcp_fin_timeout = 60
net.ipv4.tcp_syncookies = 1
默認值是0
只有在內核編譯時選擇了CONFIG_SYNCOOKIES時纔會發生做用。當出現syn等候隊列出現溢出時象對方發送syncookies。目的是爲了防止syn flood攻擊。
注意：該選項千萬不能用於那些沒有收到攻擊的高負載服務器，若是在日誌中出現synflood消息，可是調查發現沒有收到synflood攻擊，而是合法用戶的鏈接負載太高的緣由，你應該調整其它參數來提升服務器性能。參考:
tcp_max_syn_backlog
tcp_synack_retries
tcp_abort_on_overflow
syncookie嚴重的違背TCP協議，不容許使用TCP擴展，可能對某些服務致使嚴重的性能影響(如SMTP轉發)。(注意,該實現與BSD上面使用的tcp proxy同樣,是違反了RFC中關於tcp鏈接的三次握手實現的,可是對於防護syn-flood的確頗有用.)

net.ipv4.tcp_tw_recycle = 0
默認值是0
打開快速 TIME-WAIT sockets 回收。除非獲得技術專家的建議或要求﹐請不要隨意修改這個值。(作NAT的時候，建議打開它)

net.ipv4.tcp_abort_on_overflow = 0
缺省值是0
當守護進程太忙而不能接受新的鏈接，就象對方發送reset消息，默認值是false。這意味着當溢出的緣由是由於一個偶然的猝發，那麼鏈接將恢復狀態。只有在你確信守護進程真的不能完成鏈接請求時纔打開該選項，該選項會影響客戶的使用。(對待已經滿載的sendmail,apache這類服務的時候,這個能夠很快讓客戶端終止鏈接,能夠給予服務程序處理已有鏈接的緩衝機會,因此不少防火牆上推薦打開它)

net.ipv4.tcp_stdurg = 0
默認值爲0
使用 TCP urg pointer 字段中的主機請求解釋功能。大部份的主機都使用老舊的 BSD解釋，所以若是您在 Linux 打開它﹐或會致使不能和它們正確溝通。

net.ipv4.tcp_rfc1337 = 0
缺省值爲0
這個開關能夠啓動對於在RFC1337中描述的"tcp 的time-wait暗殺危機"問題的修復。啓用後，內核將丟棄那些發往time-wait狀態TCP套接字的RST 包.

net.ipv4.tcp_max_syn_backlog = 1024
對於那些依然還未得到客戶端確認的鏈接請求﹐須要保存在隊列中最大數目。對於超過 128Mb 內存的系統﹐默認值是1024 ﹐低於 128Mb 的則爲 128。若是服務器常常出現過載﹐能夠嘗試增長這個數字。警告﹗假如您將此值設爲大於1024﹐最好修改 include/net/tcp.h 裏面的 TCP_SYNQ_HSIZE ﹐以保持TCP_SYNQ_HSIZE*16<=tcp_max_syn_backlog ﹐而且編進核心以內。(SYN Flood攻擊利用TCP協議散佈握手的缺陷，僞造虛假源IP地址發送大量TCP-SYN半打開鏈接到目標系統，最終致使目標系統Socket隊列資源耗盡而沒法接受新的鏈接。爲了應付這種攻擊，現代Unix系統中廣泛採用多鏈接隊列處理的方式來緩衝(而不是解決)這種攻擊，是用一個基本隊列處理正常的徹底鏈接應用(Connect()和Accept() )，是用另外一個隊列單獨存放半打開鏈接。這種雙隊列處理方式和其餘一些系統內核措施(例如Syn-Cookies/Caches)聯合應用時，可以比較有效的緩解小規模的SYN Flood攻擊(事實證實<1000p/s)加大SYN隊列長度能夠容納更多等待鏈接的網絡鏈接數，因此對Server來講能夠考慮增大該值.)

net.ipv4.ip_local_port_range = 32768    61000
net.ipv4.ip_local_reserved_ports =
net.ipv4.igmp_max_memberships = 20
net.ipv4.igmp_max_msf = 10
net.ipv4.inet_peer_threshold = 65664
net.ipv4.inet_peer_minttl = 120
net.ipv4.inet_peer_maxttl = 600
net.ipv4.inet_peer_gc_mintime = 10
net.ipv4.inet_peer_gc_maxtime = 120
net.ipv4.tcp_orphan_retries = 0
在近端丟棄TCP鏈接以前﹐要進行多少次重試。默認值是7個﹐至關於 50秒 - 16分鐘﹐視 RTO 而定。若是您的系統是負載很大的web服務器﹐那麼也許須要下降該值﹐這類 sockets 可能會耗費大量的資源。另外參的考tcp_max_orphans 。(事實上作NAT的時候,下降該值也是好處顯著的,我本人的網絡環境中下降該值爲3)

net.ipv4.tcp_fack = 1
缺省值爲1
打開FACK擁塞避免和快速重傳功能。(注意，當tcp_sack設置爲0的時候，這個值即便設置爲1也無效)

net.ipv4.tcp_reordering = 3
默認值是3
TCP流中重排序的數據報最大數量 。 (通常有看到推薦把這個數值略微調整大一些,好比5)

net.ipv4.tcp_ecn = 2
缺省值爲0
打開TCP的直接擁塞通告功能。

net.ipv4.tcp_dsack = 1
缺省值爲1
容許TCP發送"兩個徹底相同"的SACK。

net.ipv4.tcp_mem = 753600    1004800    1507200
tcp_mem(3個INTEGER變量)：low, pressure, high
low：當TCP使用了低於該值的內存頁面數時，TCP不會考慮釋放內存。(理想狀況下，這個值應與指定給 tcp_wmem 的第 2 個值相匹配 - 這第 2 個值代表，最大頁面大小乘以最大併發請求數除以頁大小 (131072 * 300 / 4096)。 )
pressure：當TCP使用了超過該值的內存頁面數量時，TCP試圖穩定其內存使用，進入pressure模式，當內存消耗低於low值時則退出pressure狀態。(理想狀況下這個值應該是 TCP 可使用的總緩衝區大小的最大值 (204800 * 300 / 4096)。 )
high：容許全部tcp sockets用於排隊緩衝數據報的頁面量。(若是超過這個值，TCP 鏈接將被拒絕，這就是爲何不要令其過於保守 (512000 * 300 / 4096) 的緣由了。 在這種狀況下，提供的價值很大，它能處理不少鏈接，是所預期的 2.5 倍；或者使現有鏈接可以傳輸 2.5 倍的數據。 個人網絡裏爲192000 300000 732000)
通常狀況下這些值是在系統啓動時根據系統內存數量計算獲得的。

net.ipv4.tcp_wmem = 4096    16384    4194304
tcp_wmem(3個INTEGER變量)： min, default, max
min：爲TCP socket預留用於發送緩衝的內存最小值。每一個tcp socket均可以在建議之後均可以使用它。默認值爲4096(4K)。
default：爲TCP socket預留用於發送緩衝的內存數量，默認狀況下該值會影響其它協議使用的net.core.wmem_default 值，通常要低於net.core.wmem_default的值。默認值爲16384(16K)。
max: 用於TCP socket發送緩衝的內存最大值。該值不會影響net.core.wmem_max，"靜態"選擇參數SO_SNDBUF則不受該值影響。默認值爲131072(128K)。（對於服務器而言，增長這個參數的值對於發送數據頗有幫助,在個人網絡環境中,修改成了51200 131072 204800）

net.ipv4.tcp_rmem = 4096    87380    4194304
cp_rmem (3個INTEGER變量)： min, default, max
min：爲TCP socket預留用於接收緩衝的內存數量，即便在內存出現緊張狀況下tcp socket都至少會有這麼多數量的內存用於接收緩衝，默認值爲8K。
default：爲TCP socket預留用於接收緩衝的內存數量，默認狀況下該值影響其它協議使用的net.core.wmem_default 值。該值決定了在tcp_adv_win_scale、tcp_app_win和tcp_app_win=0默認值狀況下，TCP窗口大小爲65535。默認值爲87380
max：用於TCP socket接收緩衝的內存最大值。該值不會影響 net.core.wmem_max，"靜態"選擇參數 SO_SNDBUF則不受該值影響。默認值爲 128K。默認值爲87380*2 bytes。（能夠看出，.max的設置最好是default的兩倍,對於NAT來講主要該增長它,個人網絡裏爲 51200 131072 204800）

net.ipv4.tcp_app_win = 31
默認值是31
保留max(window/2^tcp_app_win, mss)數量的窗口因爲應用緩衝。當爲0時表示不須要緩衝。

net.ipv4.tcp_adv_win_scale = 2
默認值爲2
計算緩衝開銷bytes/2^tcp_adv_win_scale(若是tcp_adv_win_scale > 0)或者bytes-bytes/2^(-tcp_adv_win_scale)(若是tcp_adv_win_scale <= 0）。
net.ipv4.tcp_tw_reuse = 0

默認值是0
該文件表示是否容許從新應用處於TIME-WAIT狀態的socket用於新的TCP鏈接(這個對快速重啓動某些服務,而啓動後提示端口已經被使用的情形很是有幫助)

net.ipv4.tcp_frto = 2
net.ipv4.tcp_frto_response = 0
net.ipv4.tcp_low_latency = 0
缺省值爲0
容許 TCP/IP 棧適應在高吞吐量狀況下低延時的狀況；這個選項通常情形是的禁用。(但在構建Beowulf 集羣的時候,打開它頗有幫助)

net.ipv4.tcp_no_metrics_save = 0
net.ipv4.tcp_moderate_rcvbuf = 1
net.ipv4.tcp_tso_win_divisor = 3
net.ipv4.tcp_congestion_control = cubic
net.ipv4.tcp_abc = 0
net.ipv4.tcp_mtu_probing = 0
net.ipv4.tcp_base_mss = 512
net.ipv4.tcp_workaround_signed_windows = 0
net.ipv4.tcp_challenge_ack_limit = 100
net.ipv4.tcp_limit_output_bytes = 262144
net.ipv4.tcp_dma_copybreak = 4096
net.ipv4.tcp_slow_start_after_idle = 1
net.ipv4.cipso_cache_enable = 1
net.ipv4.cipso_cache_bucket_size = 10
net.ipv4.cipso_rbm_optfmt = 0
net.ipv4.cipso_rbm_strictvalid = 1
net.ipv4.tcp_available_congestion_control = cubic reno
net.ipv4.tcp_allowed_congestion_control = cubic reno
net.ipv4.tcp_max_ssthresh = 0
net.ipv4.tcp_thin_linear_timeouts = 0
net.ipv4.tcp_thin_dupack = 0
net.ipv4.tcp_min_tso_segs = 2
net.ipv4.udp_mem = 753600    1004800    1507200
net.ipv4.udp_rmem_min = 4096
net.ipv4.udp_wmem_min = 4096
net.ipv4.conf.all.forwarding = 0
net.ipv4.conf.all.mc_forwarding = 0
net.ipv4.conf.all.accept_redirects = 1
net.ipv4.conf.all.secure_redirects = 1
net.ipv4.conf.all.shared_media = 1
net.ipv4.conf.all.rp_filter = 0
net.ipv4.conf.all.send_redirects = 1
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.all.src_valid_mark = 0
net.ipv4.conf.all.proxy_arp = 0
net.ipv4.conf.all.medium_id = 0
net.ipv4.conf.all.bootp_relay = 0
net.ipv4.conf.all.log_martians = 0
net.ipv4.conf.all.tag = 0
net.ipv4.conf.all.arp_filter = 0
net.ipv4.conf.all.arp_announce = 2
net.ipv4.conf.all.arp_ignore = 0
net.ipv4.conf.all.arp_accept = 0
net.ipv4.conf.all.arp_notify = 0
net.ipv4.conf.all.proxy_arp_pvlan = 0
net.ipv4.conf.all.disable_xfrm = 0
net.ipv4.conf.all.disable_policy = 0
net.ipv4.conf.all.force_igmp_version = 0
net.ipv4.conf.all.promote_secondaries = 0
net.ipv4.conf.all.accept_local = 0
net.ipv4.conf.all.route_localnet = 0
net.ipv4.conf.default.forwarding = 0
net.ipv4.conf.default.mc_forwarding = 0
net.ipv4.conf.default.accept_redirects = 1
net.ipv4.conf.default.secure_redirects = 1
net.ipv4.conf.default.shared_media = 1
net.ipv4.conf.default.rp_filter = 0
net.ipv4.conf.default.send_redirects = 1
net.ipv4.conf.default.accept_source_route = 0
net.ipv4.conf.default.src_valid_mark = 0
net.ipv4.conf.default.proxy_arp = 0
net.ipv4.conf.default.medium_id = 0
net.ipv4.conf.default.bootp_relay = 0
net.ipv4.conf.default.log_martians = 0
net.ipv4.conf.default.tag = 0
net.ipv4.conf.default.arp_filter = 0
net.ipv4.conf.default.arp_announce = 2
net.ipv4.conf.default.arp_ignore = 0
net.ipv4.conf.default.arp_accept = 0
net.ipv4.conf.default.arp_notify = 0
net.ipv4.conf.default.proxy_arp_pvlan = 0
net.ipv4.conf.default.disable_xfrm = 0
net.ipv4.conf.default.disable_policy = 0
net.ipv4.conf.default.force_igmp_version = 0
net.ipv4.conf.default.promote_secondaries = 0
net.ipv4.conf.default.accept_local = 0
net.ipv4.conf.default.route_localnet = 0
net.ipv4.conf.lo.forwarding = 0
net.ipv4.conf.lo.mc_forwarding = 0
net.ipv4.conf.lo.accept_redirects = 1
net.ipv4.conf.lo.secure_redirects = 1
net.ipv4.conf.lo.shared_media = 1
net.ipv4.conf.lo.rp_filter = 0
net.ipv4.conf.lo.send_redirects = 1
net.ipv4.conf.lo.accept_source_route = 1
net.ipv4.conf.lo.src_valid_mark = 0
net.ipv4.conf.lo.proxy_arp = 0
net.ipv4.conf.lo.medium_id = 0
net.ipv4.conf.lo.bootp_relay = 0
net.ipv4.conf.lo.log_martians = 0
net.ipv4.conf.lo.tag = 0
net.ipv4.conf.lo.arp_filter = 0
net.ipv4.conf.lo.arp_announce = 2
net.ipv4.conf.lo.arp_ignore = 0
net.ipv4.conf.lo.arp_accept = 0
net.ipv4.conf.lo.arp_notify = 0
net.ipv4.conf.lo.proxy_arp_pvlan = 0
net.ipv4.conf.lo.disable_xfrm = 1
net.ipv4.conf.lo.disable_policy = 1
net.ipv4.conf.lo.force_igmp_version = 0
net.ipv4.conf.lo.promote_secondaries = 0
net.ipv4.conf.lo.accept_local = 0
net.ipv4.conf.lo.route_localnet = 0
net.ipv4.conf.eth0.forwarding = 0
net.ipv4.conf.eth0.mc_forwarding = 0
net.ipv4.conf.eth0.accept_redirects = 1
net.ipv4.conf.eth0.secure_redirects = 1
net.ipv4.conf.eth0.shared_media = 1
net.ipv4.conf.eth0.rp_filter = 0
net.ipv4.conf.eth0.send_redirects = 1
net.ipv4.conf.eth0.accept_source_route = 0
net.ipv4.conf.eth0.src_valid_mark = 0
net.ipv4.conf.eth0.proxy_arp = 0
net.ipv4.conf.eth0.medium_id = 0
net.ipv4.conf.eth0.bootp_relay = 0
net.ipv4.conf.eth0.log_martians = 0
net.ipv4.conf.eth0.tag = 0
net.ipv4.conf.eth0.arp_filter = 0
net.ipv4.conf.eth0.arp_announce = 2
net.ipv4.conf.eth0.arp_ignore = 0
net.ipv4.conf.eth0.arp_accept = 0
net.ipv4.conf.eth0.arp_notify = 0
net.ipv4.conf.eth0.proxy_arp_pvlan = 0
net.ipv4.conf.eth0.disable_xfrm = 0
net.ipv4.conf.eth0.disable_policy = 0
net.ipv4.conf.eth0.force_igmp_version = 0
net.ipv4.conf.eth0.promote_secondaries = 0
net.ipv4.conf.eth0.accept_local = 0
net.ipv4.conf.eth0.route_localnet = 0
net.ipv4.ip_forward = 0
net.ipv4.xfrm4_gc_thresh = 2097152
net.ipv4.ipfrag_high_thresh = 4194304
net.ipv4.ipfrag_low_thresh = 3145728
net.ipv4.ipfrag_time = 30
net.ipv4.icmp_echo_ignore_all = 0
net.ipv4.icmp_echo_ignore_broadcasts = 1
net.ipv4.icmp_ignore_bogus_error_responses = 1
net.ipv4.icmp_errors_use_inbound_ifaddr = 0
net.ipv4.icmp_ratelimit = 1000
net.ipv4.icmp_ratemask = 6168
net.ipv4.rt_cache_rebuild_count = 4
net.ipv4.ping_group_range = 1    0
net.ipv4.ip_no_pmtu_disc = 0
net.ipv4.ip_forward_use_pmtu = 0
net.ipv4.ipfrag_secret_interval = 600
net.ipv4.ipfrag_max_dist = 64
net.unix.max_dgram_qlen = 10
abi.vsyscall32 = 1
crypto.fips_enabled = 0
sunrpc.rpc_debug = 0
sunrpc.nfs_debug = 0
sunrpc.nfsd_debug = 0
sunrpc.nlm_debug = 0
sunrpc.transports = tcp 1048576
sunrpc.transports = udp 32768
sunrpc.transports = tcp-bc 1048576
sunrpc.udp_slot_table_entries = 16
sunrpc.tcp_slot_table_entries = 2
sunrpc.tcp_max_slot_table_entries = 65536
sunrpc.min_resvport = 665
sunrpc.max_resvport = 1023
sunrpc.tcp_fin_timeout = 15
默認值是 60
對於本端斷開的socket鏈接，TCP保持在FIN-WAIT-2狀態的時間。對方可能會斷開鏈接或一直不結束鏈接或不可預料的進程死亡。默認值爲 60 秒。過去在2.2版本的內核中是 180 秒。您能夠設置該值﹐但須要注意﹐若是您的機器爲負載很重的web服務器﹐您可能要冒內存被大量無效數據報填滿的風險﹐FIN-WAIT-2 sockets 的危險性低於 FIN-WAIT-1 ﹐由於它們最多隻吃 1.5K 的內存﹐可是它們存在時間更長。另外參考 tcp_max_orphans。(事實上作NAT的時候,下降該值也是好處顯著的,我本人的網絡環境中下降該值爲30)