当cache缓存占用太大，服务起不来，需要查看清理缓存

执行 free -m 或者 free -h ，查看缓存 

root@iZuf69hjyg1f5yaol020twZ:~# free -m
               total        used        free      shared  buff/cache   available
Mem:           15095409710584241310731
Swap:              000
root@iZuf69hjyg1f5yaol020twZ:~# free -h
               total        used        free      shared  buff/cache   available
Mem:            14Gi       4.0Gi        10Gi       2.0Mi       414Mi        10Gi
Swap:             0B          0B          0B