Grub2 内核启动参数总结

Grub2 内核启动参数总结

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部分参数

biosdevname=0
net.ifnames=0
# 注意这个配置会修改网卡的名字, 比如之前是ens192
# 添加如上两个内容后就会变成  eth0 类似于CentOS6的命令特点.
# 注意修改了网卡名称会导致机器无法上网, 需要通过控制台连接机器, 并且修改
# /etc/sysconfig/network-scprits 下面的 配置文件, 注意文件名和文件内部的name都要进行修改. 

ipv6.disable=1
# 会关闭ipv6 的设置, 查不到ipv6的地址. 

audit=0
# 关闭审计, 性能会有所提升. 

numa=off
# 关闭unma分一致性内存访问, Oracle等大型内存应用强烈建议. 

transparent_hugepage=never
# 关闭透明大页. 也是强烈建议关闭的. 

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修改方法

vim /etc/default/grub
在如下行的 最后面 双引号内部添加上一段就可以了.
GRUB_CMDLINE_LINUX=" xxxxx net.ifnames=0 ipv6.disable=1 numa=off  transparent_hugepage=never "

生效设置
grub2-mkconfig -o /boot/grub2/grub.cfg

查看是否生效
cat /boot/grub2/grub.cfg
会看到如下内容, 说明参数有效果
linux   /vmlinuz-0-rescue-1b7a5f5e75a347ed83bd41d1d51fd630 root=/dev/mapper/klas-root
ro resume=/dev/mapper/klas-swap rd.lvm.lv=klas/root rd.lvm.lv=klas/swap rhgb quiet crashkernel=1024M,high
audit=0 biosdevname=0 net.ifnames=0 ipv6.disable=1 numa=off  transparent_hugepage=never

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查看与验证

cat /sys/kernel/mm/transparent_hugepage/enabled

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结果

[root@model ~]# numactl --hardware
available: 1 nodes (0)
node 0 cpus: 0 1 2 3 4 5 6 7
node 0 size: 30877 MB
node 0 free: 29060 MB
node distances:
node   0
  0:  10

numactl -status

[root@model ~]# cat /sys/kernel/mm/transparent_hugepage/enabled
[always] madvise never

[root@model ~]# ifconfig
docker0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        ether 02:42:de:86:b6:59  txqueuelen 0  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

ens192: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.255.94  netmask 255.255.255.128  broadcast 192.168.255.127
        inet6 fe80::c873:178d:36cc:b434  prefixlen 64  scopeid 0x20<link>
        inet6 fe80::ffad:f89d:3e00:e470  prefixlen 64  scopeid 0x20<link>
        inet6 fe80::43dd:f1cf:9d69:75e1  prefixlen 64  scopeid 0x20<link>
        ether 00:50:56:b0:19:d2  txqueuelen 1000  (Ethernet)
        RX packets 458221  bytes 43424710 (41.4 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 4691  bytes 364036 (355.5 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 60  bytes 4748 (4.6 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 60  bytes 4748 (4.6 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

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重启后的效果

[root@model ~]# cat /sys/kernel/mm/transparent_hugepage/enabled
always madvise [never]
# never 意味着关闭了透明大页 

[root@model ~]# ifconfig
docker0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        inet 10.233.0.1  netmask 255.255.0.0  broadcast 10.233.255.255
        ether 02:42:b5:8c:31:c4  txqueuelen 0  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.255.94  netmask 255.255.255.128  broadcast 192.168.255.127
        ether 00:50:56:b0:19:d2  txqueuelen 1000  (Ethernet)
        RX packets 5308  bytes 352635 (344.3 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 291  bytes 45198 (44.1 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 144  bytes 10576 (10.3 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 144  bytes 10576 (10.3 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
# IPV6的地址没有了,网卡名称也发生了变化.