解决redis启动时的三个警告The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxcon

第一个警告：The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
第二个警告：overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add ‘vm.overcommit_memory = 1’ to/etc/sysctl.conf and then reboot or run the command ‘sysctl vm.overcommit_memory=1’ for this to take effect.
第三个警告：you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis. To fix thisissue run the command ‘echo never > /sys/kernel/mm/transparent_hugepage/enabled’ as root, and add it to your /etc/rc.local in order to retain thesetting after a reboot. Redis must be restarted after THP is disabled.

解决方案
考虑到redis一般都是部署在服务器上作为服务存在的。所以，本文的解决方案都是持久性配置，不是临时配置。

第一个警告
将net.core.somaxconn = 1024添加到/etc/sysctl.conf中，然后执行sysctl -p生效配置。

第二个警告
将vm.overcommit_memory = 1添加到/etc/sysctl.conf中，然后执行sysctl -p生效配置。

第三个警告
将echo never > /sys/kernel/mm/transparent_hugepage/enabled添加到/etc/rc.local中，然后执行source /etc/rc.local生效配置。

链接：https://www.jianshu.com/p/a86e0248af58