linux redis 启动警告解决方法

向右看齐 2021-08-19 19:29 500阅读 0赞

如果启动前不对linux内核做任何更改，那么redis启动会报出警告，共三个：如下图所示

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3doYXRkYXk_size_16_color_FFFFFF_t_70][]

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.

意思是：TCP  backlog设置值，511没有成功，因为 /proc/sys/net/core/somaxconn这个设置的是更小的128.

临时解决方法：（即下次启动还需要修改此值）

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

永久解决方法：（即以后启动还需要修改此值）

将其写入/etc/rc.local文件中。

baklog参数实际控制的是已经3次握手成功的还在accept queue的大小。

《linux socket 中的backlog参数介绍》[https://blog.csdn.net/whatday/article/details/103027414][https_blog.csdn.net_whatday_article_details_103027414]

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.

意思是：overcommit\_memory参数设置为0！在内存不足的情况下，后台程序save可能失败。建议在文件 /etc/sysctl.conf 中将overcommit\_memory修改为1。

临时解决方法：echo "vm.overcommit\_memory=1" > /etc/sysctl.conf

永久解决方法：将其写入/etc/sysctl.conf文件中。

参考：《linux redis WARNING overcommit\_memory is set to 0! 解决方案》[https://blog.csdn.net/whatday/article/details/103028136][https_blog.csdn.net_whatday_article_details_103028136]

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.

意思是：你使用的是透明大页，可能导致redis延迟和内存使用问题。执行 echo never > /sys/kernel/mm/transparent\_hugepage/enabled 修复该问题。

临时解决方法：

echo never > /sys/kernel/mm/transparent\_hugepage/enabled。

永久解决方法：

将其写入/etc/rc.local文件中。

参考《linux 内存管理 Transparent HugePages 透明大页 简介》[https://blog.csdn.net/whatday/article/details/103028344][https_blog.csdn.net_whatday_article_details_103028344]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3doYXRkYXk_size_16_color_FFFFFF_t_70]: /images/20210728/2dc2765d069043109c6636cebaac6cc3.png
[https_blog.csdn.net_whatday_article_details_103027414]: https://blog.csdn.net/whatday/article/details/103027414
[https_blog.csdn.net_whatday_article_details_103028136]: https://blog.csdn.net/whatday/article/details/103028136
[https_blog.csdn.net_whatday_article_details_103028344]: https://blog.csdn.net/whatday/article/details/103028344