MySQL 5.7 主库崩溃切备库

场景：MySQL主库无故宕机：判断是IO问题导致。The manual page at http://dev.mysql.com/doc/mysql/en/crashing.html containsinformation that should help you find out what is causing the crash.200118 02:11:39 mysqld_safe Number of processes running now: 0200118 02:11:39 mysqld_safe mysqld restarted 原来主库的my.cnf： # For advice on how to change settings please see # http://dev.mysql.com/doc/refman/5.7/en/server-configuration-defaults.html # *** DO NOT EDIT THIS FILE. It's a template which will be copied to the # *** default location during install, and will be replaced if you # *** upgrade to a newer version of MySQL. [mysqld] # Remove leading # and set to the amount of RAM for the most important data # cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%. # innodb_buffer_pool_size = 128M # Remove leading # to turn on a very important data integrity option: logging # changes to the binary log between backups. # log_bin # These are commonly set, remove the # and set as required. # basedir = ..... # datadir = ..... # port = ..... # server_id = ..... # socket = ..... basedir=/usr/local/mysql datadir=/data/bak1 socket=/tmp/mysql.sock server-id =11224722 default_password_lifetime=0 log-bin=/data/bak1/mysql-bin2 expire_logs_days = 1 max_binlog_size =600M binlog_format = MIXED #max_allowed_packet =1*1024*1024*1024 max_allowed_packet =1024M event_scheduler = 1 transaction-isolation = READ-COMMITTED max_connections=5000 innodb_buffer_pool_size = 80G # Remove leading # to set options mainly useful for reporting servers. # The server defaults are faster for transactions and fast SELECTs. # Adjust sizes as needed, experiment to find the optimal values. # join_buffer_size = 128M # sort_buffer_size = 2M # read_rnd_buffer_size = 2M  sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES 1.确保所有的relay log全部更新完毕，在每个从库上执行stop slave io_thread; show processlist; 直到看到Has read all relay log,则表 示从库更新都执行完毕了。2.登陆所有从库，查看master.info文件，对比选择pos最大的作为新的主库，这里我们选择192.168.112.10为新的主库。 3.登陆192.168.112.10，执行stop slave; 并进入数据库目录，删除master.info和relay-log.info文件, 配置my.cnf文件， 开启log-bin,如果有 log-slaves-updates和read-only则要注释掉，执行reset master。 新主库的my.cnf： [mysqld] #datadir=/var/lib/mysql #socket=/var/lib/mysql/mysql.sock datadir=/data/db socket=/tmp/mysql.sock server-id =111210 log-bin = /data/db/mysql-bin.log # binlog_format = MIXED #relay-log = rep_relay_log1 #relay-log-index = rep_relay_log1 #log-error=/data/bak/mysqld1.err #skip-slave-start = 1 default_password_lifetime=0 # binlog-ignore-db=mysql   #expire_logs_days =7 max_connections = 2000 # user=mysql # Disabling symbolic-links is recommended to prevent assorted security risks #symbolic-links=0 max_allowed_packet =1024M #master_info_repository=table #relay_log_info_repository=table #relay_log_recovery=1 #transaction-isolation = READ-COMMITTED sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES [mysqld_safe] log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid 4.SHOW MASTER STATUS; 查询主库状态。 OK。