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文章标签 ‘nf_conntrack_max’

iptables restart带来的隐性问题

2016年6月2日 没有评论

高并发服务器,忽然性能变差,几经周折,某大牛发现一些内核参数因iptables的调整被自动重置了。
比如:/proc/sys/net/netfilter/nf_conntrack_max 被复位成65535了

解决办法:
修改/etc/sysconfig/iptables-config中的IPTABLES_MODULES_UNLOAD为no即可解决:

# Unload modules on restart and stop
#   Value: yes|no,  default: yes
# This option has to be 'yes' to get to a sane state for a firewall
# restart or stop. Only set to 'no' if there are problems unloading netfilter
# modules.
IPTABLES_MODULES_UNLOAD="no"

iptables的调整很常见,我从来没意识到会引起netfilter模块参数的重置。估计会有很多小白像我一样~

高并发服务所在Linux内核参数调整

2015年12月31日 没有评论

nginx所在linux,http访问出现大量超时,调整sysctl.conf中两个参数后恢复正常

net.nf_conntrack_max = 655360
net.netfilter.nf_conntrack_max = 655350

把相关的配置都留存备忘。

open files限制

# cat /etc/security/limits.conf | grep -v "\#"
* soft nproc 655350
* hard nproc 655350
* soft nofile 655350
* hard nofile 655350

内核参数

# less sysctl.conf  | grep -v "\#"
net.ipv4.ip_forward = 0
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.default.accept_source_route = 0
kernel.sysrq = 0
kernel.core_uses_pid = 1
net.ipv4.tcp_syncookies = 1
net.bridge.bridge-nf-call-ip6tables = 0
net.bridge.bridge-nf-call-iptables = 0
net.bridge.bridge-nf-call-arptables = 0
kernel.msgmnb = 65536
kernel.msgmax = 65536
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
net.ipv4.tcp_fin_timeout = 1
net.ipv4.tcp_keepalive_time = 1200
net.ipv4.tcp_mem = 94500000 915000000 927000000
net.ipv4.tcp_timestamps = 1
net.ipv4.tcp_synack_retries = 1
net.ipv4.tcp_syn_retries = 1
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.core.netdev_max_backlog = 262144
net.core.somaxconn = 262144
net.ipv4.tcp_max_orphans = 3276800
net.ipv4.tcp_max_syn_backlog = 262144
net.core.wmem_default = 8388608
net.core.rmem_default = 8388608
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
net.nf_conntrack_max = 655360
net.netfilter.nf_conntrack_max = 655350
net.netfilter.nf_conntrack_tcp_timeout_time_wait = 10
net.netfilter.nf_conntrack_tcp_timeout_established = 600
net.ipv4.tcp_max_tw_buckets = 5000
net.ipv4.ip_local_port_range = 1024 65535

只有net.ipv4.tcp_timestamps = 1时,net.ipv4.tcp_tw_reuse和net.ipv4.tcp_tw_recycle的配置才有效。