1 overcommit_memory参数为 0

在低内存的时候会无法fork进程，导致数据保存失败

处理：

在/etc/sysctl.conf中添加vm.overcommit_memory = 1，然后重启机器，或者sysctl vm.overcommit_memory=1，本次有效

2 you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis. To fix this issue 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 the setting after a reboot. Redis must be restarted after THP is disabled.

3 /proc/sys/net/core/somaxconn is set to the lower value of 128

在/etc/sysctl.conf中添加net.core.somaxconn = 8196（可以更大）