刚启动检测正常后就其他节点都 sdown ，每个节点都是一样的报错，报下面的错：
10908:X 22 Mar 16:33:46.571 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
10908:X 22 Mar 16:33:46.576 # Sentinel ID is 0567d030532d64e9983ea318b91c465c5e6ae446
10908:X 22 Mar 16:33:46.576 # +monitor master mymaster 192.168.21.241 6379 quorum 3
10908:X 22 Mar 16:33:46.577 * +slave slave 192.168.21.242:6379 192.168.21.242 6379 @ mymaster 192.168.21.241 6379
10908:X 22 Mar 16:33:46.579 * +slave slave 192.168.21.244:6379 192.168.21.244 6379 @ mymaster 192.168.21.241 6379
10908:X 22 Mar 16:33:47.815 * +sentinel sentinel ed36ffb02a686db2c306dc49200bf36af0f0b823 192.168.21.241 26379 @ mymaster 192.168.21.241 6379
10908:X 22 Mar 16:33:48.159 * +sentinel sentinel 011a32fae263fc160b695cb09e72f4e5d4accde5 192.168.21.242 26379 @ mymaster 192.168.21.241 6379
10908:X 22 Mar 16:34:16.665 # +sdown slave 192.168.21.244:6379 192.168.21.244 6379 @ mymaster 192.168.21.241 6379
10908:X 22 Mar 16:34:17.825 # +sdown sentinel ed36ffb02a686db2c306dc49200bf36af0f0b823 192.168.21.241 26379 @ mymaster 192.168.21.241 6379
10908:X 22 Mar 16:34:18.195 # +sdown sentinel 011a32fae263fc160b695cb09e72f4e5d4accde5 192.168.21.242 26379 @ mymaster 192.168.21.241 6379
这两个参数是必须开启的：
protected-mode no
daemonize yes