Shulou(Shulou.com)06/02 Report--

If no changes are made to the linux kernel before startup, redis startup will report three warnings: as shown in the following figure

First warning: The TCP backlog setting of 511 cannot be enforced because / proc/sys/net/core/somaxconn is set to the lower value of 128.

The TCP backlog setting value 511 did not succeed because the / proc/sys/net/core/somaxconn setting is a smaller 128.

Temporary solution: (that is, you need to modify this value the next time you start)

Echo 511 > / proc/sys/net/core/somaxconn

Permanent solution: (that is, this value needs to be modified for later startup)

Write it to the / etc/rc.local file.

The baklog parameter actually controls the size of the accept queue that has been shaken successfully for 3 times.

Refer to backlog in linux for detailed explanation.

Second warning: 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.

The overcommit_memory parameter is set to 0! The daemon save may fail in the case of insufficient memory. It is recommended that you modify overcommit_memory to 1 in the file / etc/sysctl.conf.

Temporary solution: echo "vm.overcommit_memory=1" > / etc/sysctl.conf

Permanent solution: write it to the / etc/sysctl.conf file.

Reference: questions about redis overcommit_memory under linux

The third warning: 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.

You are using transparent large pages, which may cause redis latency and memory usage problems. Execute echo never > / sys/kernel/mm/transparent_hugepage/enabled to fix the problem.

Temporary solution:

Echo never > / sys/kernel/mm/transparent_hugepage/enabled

Permanent solution:

Write it to the / etc/rc.local file.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.