redis性能调优笔记（can not get Resource from jedis pool和jedis connect time out）

################################### LIMITS ####################################

# Set the max number of connected clients at the same time. By default
# this limit is set to 10000 clients, however if the Redis server is not
# able to configure the process file limit to allow for the specified limit
# the max number of allowed clients is set to the current file limit
# minus 32 (as Redis reserves a few file descriptors for internal uses).
#
# Once the limit is reached Redis will close all the new connections sending
# an error 'max number of clients reached'.
#
maxclients 10000   

#<domain>      <type>  <item>         <value>
arch          soft    nofile          100000
arch          hard    nofile          100000

public void set(String key, String value) {
        Jedis jedis = null;
        boolean broken = false;
        try {
            jedis = jedisPool.getResource();
            jedis.set(key, value);
        } catch (JedisConnectionException ex) {
            jedisPool.returnBrokenResource(jedis);
            broken = true;
            throw ex;
        }finally {
            if (jedis != null && !broken) {
                jedisPool.returnResource(jedis);
            }
        }
    }

################################## SLOW LOG ###################################

# The Redis Slow Log is a system to log queries that exceeded a specified
# execution time. The execution time does not include the I/O operations
# like talking with the client, sending the reply and so forth,
# but just the time needed to actually execute the command (this is the only
# stage of command execution where the thread is blocked and can not serve
# other requests in the meantime).
#
# You can configure the slow log with two parameters: one tells Redis
# what is the execution time, in microseconds, to exceed in order for the
# command to get logged, and the other parameter is the length of the
# slow log. When a new command is logged the oldest one is removed from the
# queue of logged commands.

# The following time is expressed in microseconds, so 1000000 is equivalent
# to one second. Note that a negative number disables the slow log, while
# a value of zero forces the logging of every command.
slowlog-log-slower-than 10000

# There is no limit to this length. Just be aware that it will consume memory.
# You can reclaim memory used by the slow log with SLOWLOG RESET.
slowlog-max-len 128

10.93.84.53:6379> slowlog get 10
 1) 1) (integer) 105142
    2) (integer) 1503742342
    3) (integer) 66494
    4) 1) "KEYS"
       2) "prometheus:report:fuse:*"
 2) 1) (integer) 105141
    2) (integer) 1503742336
    3) (integer) 67145
    4) 1) "KEYS"
       2) "prometheus:report:fuse:*"

16890:M 21 Aug 12:43:18.354 # 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.

// 修改这个文件
vim /etc/sysctl.conf
// 加上下面这个配置
vm.overcommit_memory = 1
// 在不重启机器的情况下生效
sysctl vm.overcommit_memory=1