Mysql5.6主从参数详解

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mysql5.6主从参数详解

server_id = 2
#binlog
log-bin = /data1/mysql/binlog/binlog
#谨慎设置binlog_format=MIXED
binlog_format = ROW 
binlog-row-image = minimal
#gtid_mode = ON
#enforce-gtid-consistency = true
binlog_cache_size = 4M
max_binlog_size = 1G
max_binlog_cache_size = 2G
sync_binlog = 1
slave-skip-errors = 1062
expire_logs_days = 3
slave_parallel_workers = 4
#relay log
relay-log = /data1/mysql/relaylog/relaylog
max_relay_log_size = 1G
relay_log_purge = 1
relay_log_recovery = 1
binlog_checksum = CRC32
slave_allow_batching = 1
master_verify_checksum = 1
slave_sql_verify_checksum = 1
binlog_rows_query_log_events = 1
master_info_repository = TABLE
relay_log_info_repository = TABLE
log_slave_updates

讲解

#我在线上的还是后面一种写法 
server_id = 2之前的写法是:server-id = 2

sync_binlog = 1
默认情况下,并不是每次写入时都将binlog与硬盘同步。因此如果操作系统或机器(不仅仅是MySQL服务器)崩溃,有可能binlog中最后的语句丢 失了。要想防止这种情况,你可以使用sync_binlog全局变量(1是最安全的值,但也是最慢的),使binlog在每N次binlog写入后与硬盘 同步。即使sync_binlog设置为1,出现崩溃时,也有可能表内容和binlog内容之间存在不一致性。如果使用InnoDB表,MySQL服务器 处理COMMIT语句,它将整个事务写入binlog并将事务提交到InnoDB中。如果在两次操作之间出现崩溃,重启时,事务被InnoDB回滚,但仍 然存在binlog中。可以用--innodb-safe-binlog选项来增加InnoDB表内容和binlog之间的一致性。(注释:在MySQL 5.1中不需要--innodb-safe-binlog;由于引入了XA事务支持,该选项作废了),该选项可以提供更大程度的安全,使每个事务的 binlog(sync_binlog =1)和(默认情况为真)InnoDB日志与硬盘同步,该选项的效果是崩溃后重启时,在滚回事务后,MySQL服务器从binlog剪切回滚的 InnoDB事务。这样可以确保binlog反馈InnoDB表的确切数据等,并使从服务器保持与主服务器保持同步(不接收 回滚的语句)。

server_id = 2之前的写法是:server-id = 2

gtid_mode = ON
enforce-gtid-consistency = true
这两个参数是启用mysql5.6中的UUID同步模式,两个参数必须一起打开,否则报错,slave在做同步复制时,无须找到binlog日志和POS点,直接change master to master_auto_position=1即可,自动找点同步。
GTID的局限性: (鉴于这些局限性,慎用)
1.GTID同步复制是基于事务。所以Myisam表不支持,这可能导致多个GTID分配给同一个事务。
2.CREATE TABLE ... SELECT语句不支持。因为该语句会被拆分成create table 和insert两个事务,并且这个两个事务被分配了同一个GTID,这会导致insert被备库忽略掉。
3.不支持CREATE TEMPORARY TABLE、DROP TEMPORARY TABLE 临时表操作。
启用之后进行同步语句:
CHANGE MASTER TO MASTER_HOST='60.2.212.190', MASTER_PORT=3306, MASTER_USER='repl',MASTER_PASSWORD='H7RYbCkGHmm_P1XO', master_auto_position=1;
不启动的话同步语句和之前一样:
change master to
master_host='192.168.100.190',
master_user='repl',
master_password='123456',
master_port=3306,
master_log_file='binlog.000001',
master_log_pos=1287;
start slave;
在5.6的版本中,启动主从为:start slave,而之前用slave start也可以。

binlog-row-image=minimal,这个选项允许应用程序只能对行的镜像数据进行复制,而不在关心行是否已经进行了DML操作。这提高了主从机器的复制吞吐量,减少了二进制日志所占用的磁盘空间、网络资源和内存占用。

slave_parallel_workers = 4 默认是0,不开启,最大并发数为1024个线程。主从复制启用4个sql线程,提高从服务器吞吐量,减少延迟,使用并发的 SQL 线程对不同数据库并行应用事件,如果只同步一个库的,指定为0,否则会阻塞。

binlog_checksum = CRC32
slave_allow_batching = 1
master_verify_checksum = 1
slave_sql_verify_checksum = 1
binlog_rows_query_log_events = 1
这四个参数是启用binlog/relaylog的校验,防止日志出错

relay_log_purge = 1
relay_log_recovery = 1
这两个是启用relaylog的自动修复功能,避免由于网络之类的外因造成日志损坏,主从停止。

master_info_repository = TABLE
relay_log_info_repository = TABLE
这两个参数会将master.info和relay.info保存在表中,默认是Myisam引擎,官方建议用
alter table  slave_master_info engine=innodb;
alter table  slave_relay_log_info engine=innodb;
alter table  slave_worker_info engine=innodb;
改为Innodb引擎,防止表损坏后自行修复。 


下面是我的配置

[[email protected] ~]# cat /etc/my.cnf
[client]
port		= 3306
socket		= /tmp/mysql.sock

[mysqld]
user = mysql
#datadir = /mysql/
datadir = /apps/mysql
port		= 3306
socket		= /tmp/mysql.sock

#slow log
slow_query_log
long_query_time = 1
slow_query_log_file = /logs/mysql/slow-mysql.log
#slow_query_log_file = /apps/mysql/logs/slow-mysql.log

#character
collation_server=utf8_unicode_ci
character_set_server=utf8

#security 
local-infile=0


#memory
thread_cache_size = 512
table_open_cache = 4096
sort_buffer_size = 256K
join_buffer_size = 1M
tmp_table_size = 128M
max_heap_table_size = 128M
thread_stack = 192K
query_cache_size = 64M
query_cache_limit = 2M

#network
skip-name-resolve
max_connections = 2000
max_connect_errors=1844674407370954751
connect_timeout = 30
max_allowed_packet = 64M
interactive_timeout = 43200
wait_timeout = 86400

#server
back_log = 1000
skip-external-locking
thread_concurrency = 8
ft_min_word_len = 4
transaction_isolation = READ-COMMITTED

#log
log_output=FILE
log_warnings
log-error=//logs/mysql/mysqld-error.log
#log-error=/apps/mysql/logs/mysqld-error.log

#bin-log
log-bin = /apps/mysql/binlog/mysql-bin
#log-bin = mysql-bin
binlog_format=mixed
sync_binlog = 15
expire_logs_days=3
#expire_logs_days=7
max_binlog_size=1G
server-id = 2

#myisam
key_buffer_size = 512M
read_buffer_size = 512K
read_rnd_buffer_size = 512K
bulk_insert_buffer_size = 64M
myisam_sort_buffer_size = 128M
myisam_max_sort_file_size = 10G
myisam_repair_threads = 1

#innodb
innodb_file_per_table=1
innodb_file_format=barracuda
innodb_strict_mode=0
innodb_additional_mem_pool_size = 32M
innodb_buffer_pool_size = 2G
innodb_data_file_path = ibdata1:4G:autoextend
innodb_file_io_threads = 4
innodb_force_recovery=0
innodb_thread_concurrency = 8
innodb_flush_log_at_trx_commit = 0
innodb_log_buffer_size = 16M
innodb_log_file_size = 256M
innodb_log_files_in_group = 3
innodb_autoinc_lock_mode = 2
innodb_max_dirty_pages_pct = 90
innodb_flush_method=O_DIRECT
innodb_lock_wait_timeout = 30
innodb_table_locks = 0


[mysqldump]
quick
max_allowed_packet = 16M

[mysql]
no-auto-rehash

[myisamchk]
key_buffer_size = 512M
sort_buffer_size = 512M
read_buffer = 2M
write_buffer = 2M

[mysqlhotcopy]
interactive-timeout 

参考

http://wangwei007.blog.51cto.com/68019/1205298


谨慎设置binlog_format=MIXED