PXC简介
Percona XtraDB Cluster（简称PXC集群）提供了MySQL高可用的一种实现方法。
1.集群是有节点组成的，推荐配置至少3个节点，但是也可以运行在2个节点上。
2.每个节点都是普通的mysql/percona服务器，可以将现有的数据库服务器组成集群，反之，也可以将集群拆分成单独的服务器。
3.每个节点都包含完整的数据副本。
PXC集群主要由两部分组成：Percona Server with XtraDB和Write Set Replication patches（使用了Galera library，一个通用的用于事务型应用的同步、多主复制插件）。
PXC特性：
1，同步复制，事务要么在所有节点提交或不提交。
2，多主复制，可以在任意节点进行写操作。
3，在从服务器上并行应用事件，真正意义上的并行复制。
4，节点自动配置，数据一致性，不再是异步复制。
PXC劣势：
1、 当前版本（5.6.20）的复制只支持InnoDB引擎，其他存储引擎的更改不复制。然而，DDL（Data Definition Language） 语句在statement级别被复制，并且，对mysql.*表的更改会基于此被复制。例如CREATE USER...语句会被复制，但是 INSERT INTO mysql.user...语句则不会。（也可以通过wsrep_replicate_myisam参数开启myisam引擎的复制，但这是一个实验性的参数）。
2、PXC集群一致性控制机制，事有可能被终止，原因如下：集群允许在两个节点上同时执行操作同一行的两个事务，但是只有一个能执行成功，另一个会被终止，集群会给被终止的客户端返回死锁错误(Error: 1213 SQLSTATE: 40001 (ER_LOCK_DEADLOCK)).
3、写入效率取决于节点中最弱的一台，因为PXC集群采用的是强一致性原则，一个更改操作在所有节点都成功才算执行成功。
环境介绍：
操作系统版本:Centos-6.5-X64
数据库版本:Percona-Server-5.6.15-rel63.0.tar
192.168.3.81 node1
192.168.3.82 node2
192.168.3.83 node3
1.安装 Percona mysql(所有节点安装)
安装源
rpm -ivh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
安装Precona XtraDB Cluster所需要的扩展包
yum -y install cmake gcc gcc-c++ libaio libaio-devel automake autoconf bzr bisonlibtool ncurses5-devel boost
安装perl组件（xtrabackup需要的组件）
yum -y install perl-DBD-MySQL perl-DBI perl-Time-HiRes
安装socat (Socat是一个在两个独立数据的双向传输之间起到中继作用的软件）
配置好epel源之后，可直接执行 yum -y install socat若无法yum安装socat，则按照以下步骤编译安装wget http://www.dest-unreach.org/socat/download/socat-1.7.2.4.tar.gztar zxvf socat-1.7.2.4.tar.gz./configuremake && make install安装Percona-XtraDB-Cluster及其相关组件wget http://www.percona.com/downloads/percona-release/percona-release-0.0-1.x86_64.rpm
rpm -ivh percona-release-0.0-1.x86_64.rpm
yum -y install Percona-Server-shared-56 Percona-Server-client-56 Percona-Server-server-56
二．初始化Percona-XtraDB-Cluster集群Percona mysql配置文件修改
配置 /etc/my.cnf，(所有节点安装)：
# vim /etc/my.cnf [mysqld] innodb_buffer_pool_size = 1024M //innodb_buffer_pool_size内存的80% datadir = /data/mysql port = 3306 server_id = 81 //server_id必须要不一样 socket = /tmp/mysql.sock log-bin=mysql-bin expire_logs_days = 10 sort_buffer_size = 1M join_buffer_size = 1M query_cache_size = 512M query_cache_limit = 2M query_cache_min_res_unit = 2k thread_stack = 192K tmp_table_size = 246M max_heap_table_size = 246M key_buffer_size = 300M read_buffer_size = 1M read_rnd_buffer_size = 16M bulk_insert_buffer_size = 64M slow_query_log = 1 log-error = /data/mysql/log/error.log long_query_time = 2 log-queries-not-using-indexes = ON slow_query_log_file = /data/mysql/log/slowquery.log sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES general_log = 1 //数据库执行日志开关,一般不打开 general_log_file = /data/mysql/log/mysql-general.log //数据库执行日志文件,一般不打开
创建所需目录，(所有节点安装)：
mkdir -p /data/mysql/log
chown mysql.mysql /data/mysql/log
初始化数据库，(所有节点安装)：
mysql_install_db --user=mysql --datadir=/data/mysql/etc/init.d/mysql startmysqladmin -u root password ‘123456‘ -S /tmp/mysql.sock //首次修改mysql密码因为XtraDB Cluster的软件包与原有软件包冲突：
/etc/init.d/mysql stoprpm -qa | grep Percona-Server | grep -v compat |xargs rpm -e --nodeps安装Percona XtraDB Cluster 5.6 (所有节点安装)yum -y install Percona-XtraDB-Cluster-server-56 Percona-XtraDB-Cluster-client-56 Percona-XtraDB-Cluster-galera-3 添加 XtraDB Cluster 的支持，(所有节点安装)vim /etc/my.cnf 在[mysqld]模块下面增加下面内容: # xtradb cluster settings binlog_format = ROW wsrep_cluster_name = PXC wsrep_cluster_address = gcomm://192.168.3.81,192.168.3.82,192.168.3.83 wsrep_node_address = 192.168.3.81 //注意，每台服务器需要将 wsrep_node_address 设置为本机的IP地址或主机名。 wsrep_provider = /usr/lib64/libgalera_smm.so wsrep_sst_method = rsync innodb_locks_unsafe_for_binlog = 1 innodb_autoinc_lock_mode = 2 default_storage_engine=InnoDB
初始化第一个Node:/etc/init.d/mysql bootstrap-pxc //第一个节点才使用mysql> show global status like ‘wsrep%‘; +------------------------------+--------------------------------------+ | Variable_name | Value | +------------------------------+--------------------------------------+ | wsrep_local_state_uuid | fdfec3ab-d9e8-11e4-94aa-ae45256a81fb | | wsrep_protocol_version | 7 | | wsrep_last_committed | 2 | | wsrep_replicated | 0 | | wsrep_replicated_bytes | 0 | | wsrep_repl_keys | 0 | | wsrep_repl_keys_bytes | 0 | | wsrep_repl_data_bytes | 0 | | wsrep_repl_other_bytes | 0 | | wsrep_received | 2 | | wsrep_received_bytes | 141 | | wsrep_local_commits | 0 | | wsrep_local_cert_failures | 0 | | wsrep_local_replays | 0 | | wsrep_local_send_queue | 0 | | wsrep_local_send_queue_max | 1 | | wsrep_local_send_queue_min | 0 | | wsrep_local_send_queue_avg | 0.000000 | | wsrep_local_recv_queue | 0 | | wsrep_local_recv_queue_max | 1 | | wsrep_local_recv_queue_min | 0 | | wsrep_local_recv_queue_avg | 0.000000 | | wsrep_local_cached_downto | 0 | | wsrep_flow_control_paused_ns | 0 | | wsrep_flow_control_paused | 0.000000 | | wsrep_flow_control_sent | 0 | | wsrep_flow_control_recv | 0 | | wsrep_cert_deps_distance | 0.000000 | | wsrep_apply_oooe | 0.000000 | | wsrep_apply_oool | 0.000000 | | wsrep_apply_window | 0.000000 | | wsrep_commit_oooe | 0.000000 | | wsrep_commit_oool | 0.000000 | | wsrep_commit_window | 0.000000 | | wsrep_local_state | 4 | | wsrep_local_state_comment | Synced | | wsrep_cert_index_size | 0 | | wsrep_causal_reads | 0 | | wsrep_cert_interval | 0.000000 | | wsrep_incoming_addresses | 192.168.3.81:3306 | | wsrep_evs_delayed | | | wsrep_evs_evict_list | | | wsrep_evs_repl_latency | 0/0/0/0/0 | | wsrep_evs_state | OPERATIONAL | | wsrep_gcomm_uuid | 597ae492-dcc6-11e4-ba30-e6dfd92be1c6 | | wsrep_cluster_conf_id | 1 | | wsrep_cluster_size | 1 | | wsrep_cluster_state_uuid | fdfec3ab-d9e8-11e4-94aa-ae45256a81fb | | wsrep_cluster_status | Primary | | wsrep_connected | ON | | wsrep_local_bf_aborts | 0 | | wsrep_local_index | 0 | | wsrep_provider_name | Galera | | wsrep_provider_vendor | Codership Oy <info@codership.com> | | wsrep_provider_version | 3.9(r93aca2d) | | wsrep_ready | ON | +------------------------------+--------------------------------------+
"wsrep_cluster_size" 为 1，因为目前Cluster中只有一个Node。mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | log | | mysql | | performance_schema | | test | +--------------------+ 5 rows in set (0.00 sec) mysql> create database liu; Query OK, 1 row affected (0.00 sec) mysql> use liu Database changed mysql> create table liu01 (id int,name char(4)); Query OK, 0 rows affected (0.05 sec) mysql> show tables; +---------------+ | Tables_in_liu | +---------------+ | liu01 | +---------------+ 1 row in set (0.01 sec)
[root@M1905 mysql]# mysql -u root -p123456 -S /tmp/mysql.sock mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | liu | | log | | mysql | | performance_schema | | test | +--------------------+ 6 rows in set (0.00 sec) mysql> use liu Database changed mysql> show tables; +---------------+ | Tables_in_liu | +---------------+ | liu01 | +---------------+ 1 row in set (0.00 sec)
查看Cluster的状态：
mysql> show global status like ‘wsrep%‘; +------------------------------+--------------------------------------+ | Variable_name | Value | +------------------------------+--------------------------------------+ | wsrep_local_state_uuid | fdfec3ab-d9e8-11e4-94aa-ae45256a81fb | | wsrep_protocol_version | 7 | | wsrep_last_committed | 7 | | wsrep_replicated | 0 | | wsrep_replicated_bytes | 0 | | wsrep_repl_keys | 0 | | wsrep_repl_keys_bytes | 0 | | wsrep_repl_data_bytes | 0 | | wsrep_repl_other_bytes | 0 | | wsrep_received | 4 | | wsrep_received_bytes | 510 | | wsrep_local_commits | 0 | | wsrep_local_cert_failures | 0 | | wsrep_local_replays | 0 | | wsrep_local_send_queue | 0 | | wsrep_local_send_queue_max | 1 | | wsrep_local_send_queue_min | 0 | | wsrep_local_send_queue_avg | 0.000000 | | wsrep_local_recv_queue | 0 | | wsrep_local_recv_queue_max | 1 | | wsrep_local_recv_queue_min | 0 | | wsrep_local_recv_queue_avg | 0.000000 | | wsrep_local_cached_downto | 7 | | wsrep_flow_control_paused_ns | 0 | | wsrep_flow_control_paused | 0.000000 | | wsrep_flow_control_sent | 0 | | wsrep_flow_control_recv | 0 | | wsrep_cert_deps_distance | 1.000000 | | wsrep_apply_oooe | 0.000000 | | wsrep_apply_oool | 0.000000 | | wsrep_apply_window | 1.000000 | | wsrep_commit_oooe | 0.000000 | | wsrep_commit_oool | 0.000000 | | wsrep_commit_window | 1.000000 | | wsrep_local_state | 4 | | wsrep_local_state_comment | Synced | | wsrep_cert_index_size | 3 | | wsrep_causal_reads | 0 | | wsrep_cert_interval | 0.000000 | | wsrep_incoming_addresses | 192.168.3.82:3306,192.168.3.81:3306 | | wsrep_evs_delayed | | | wsrep_evs_evict_list | | | wsrep_evs_repl_latency | 0/0/0/0/0 | | wsrep_evs_state | OPERATIONAL | | wsrep_gcomm_uuid | 16e598fb-dccb-11e4-9ca9-cb37e03eb618 | | wsrep_cluster_conf_id | 2 | | wsrep_cluster_size | 2 | | wsrep_cluster_state_uuid | fdfec3ab-d9e8-11e4-94aa-ae45256a81fb | | wsrep_cluster_status | Primary | | wsrep_connected | ON | | wsrep_local_bf_aborts | 0 | | wsrep_local_index | 0 | | wsrep_provider_name | Galera | | wsrep_provider_vendor | Codership Oy <info@codership.com> | | wsrep_provider_version | 3.9(r93aca2d) | | wsrep_ready | ON | +------------------------------+--------------------------------------+
参数 "wsrep_cluster_size" 变为了 2。因为目前Cluster中已经有2个Node了。
下面就可按照同样步骤，添加更多节点到Cluster中了，在这个测试环境中，我们一共有3个Node。添加第三个节点到集群中service mysql start[root@M1905 mysql]# mysql -u root -p123456 -S /tmp/mysql.sock mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | liu | | log | | mysql | | performance_schema | | test | +--------------------+ 6 rows in set (0.00 sec) mysql> use liu Database changed mysql> show tables; +---------------+ | Tables_in_liu | +---------------+ | liu01 | +---------------+ 1 row in set (0.00 sec)
测试Cluster功能
7.1模拟192.168.3.81节点1宕机
[root@M1905 ~]# service mysql stop
Shutting down MySQL (Percona XtraDB Cluster).... SUCCESS!
[root@M1905 ~]# netstat -tunlp
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 809/sshd
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 898/master
//在任意其它节的查看cluster状态
mysql> show global status like ‘wsrep%‘; //在任意其它节的查看cluster状态 +------------------------------+---------------------------------------------------+ | Variable_name | Value | +------------------------------+---------------------------------------------------+ | wsrep_local_state_uuid | fdfec3ab-d9e8-11e4-94aa-ae45256a81fb | | wsrep_protocol_version | 7 | | wsrep_last_committed | 7 | | wsrep_replicated | 0 | | wsrep_replicated_bytes | 0 | | wsrep_repl_keys | 0 | | wsrep_repl_keys_bytes | 0 | | wsrep_repl_data_bytes | 0 | | wsrep_repl_other_bytes | 0 | | wsrep_received | 4 | | wsrep_received_bytes | 489 | | wsrep_local_commits | 0 | | wsrep_local_cert_failures | 0 | | wsrep_local_replays | 0 | | wsrep_local_send_queue | 0 | | wsrep_local_send_queue_max | 1 | | wsrep_local_send_queue_min | 0 | | wsrep_local_send_queue_avg | 0.000000 | | wsrep_local_recv_queue | 0 | | wsrep_local_recv_queue_max | 1 | | wsrep_local_recv_queue_min | 0 | | wsrep_local_recv_queue_avg | 0.000000 | | wsrep_local_cached_downto | 0 | | wsrep_flow_control_paused_ns | 0 | | wsrep_flow_control_paused | 0.000000 | | wsrep_flow_control_sent | 0 | | wsrep_flow_control_recv | 0 | | wsrep_cert_deps_distance | 0.000000 | | wsrep_apply_oooe | 0.000000 | | wsrep_apply_oool | 0.000000 | | wsrep_apply_window | 0.000000 | | wsrep_commit_oooe | 0.000000 | | wsrep_commit_oool | 0.000000 | | wsrep_commit_window | 0.000000 | | wsrep_local_state | 4 | | wsrep_local_state_comment | Synced | | wsrep_cert_index_size | 0 | | wsrep_causal_reads | 0 | | wsrep_cert_interval | 0.000000 | | wsrep_incoming_addresses | 192.168.3.82:3306,192.168.3.83:3306 | | wsrep_evs_delayed | | | wsrep_evs_evict_list | | | wsrep_evs_repl_latency | 0.000483336/0.000670287/0.000857238/0.000186951/2 | | wsrep_evs_state | OPERATIONAL | | wsrep_gcomm_uuid | 6c70c34d-dccd-11e4-a9fd-a30f91414348 | | wsrep_cluster_conf_id | 4 | | wsrep_cluster_size | 2 | | wsrep_cluster_state_uuid | fdfec3ab-d9e8-11e4-94aa-ae45256a81fb | | wsrep_cluster_status | Primary | | wsrep_connected | ON | | wsrep_local_bf_aborts | 0 | | wsrep_local_index | 1 | | wsrep_provider_name | Galera | | wsrep_provider_vendor | Codership Oy <info@codership.com> | | wsrep_provider_version | 3.9(r93aca2d) | | wsrep_ready | ON | +------------------------------+---------------------------------------------------+
#发现wsrep_incoming_addresses的192.168.3.81:3306不存在，并且wsrep_cluster_size 可用节点为2.
7.2在192.168.3.83节点3上面插入新数据
mysql> select * from liu01; +------+------+ | id | name | +------+------+ | 1 | aa | +------+------+ 1 row in set (0.00 sec) mysql> insert into liu01 values(2,‘bb‘); mysql> select * from liu01; +------+------+ | id | name | +------+------+ | 1 | aa | | 2 | bb | +------+------+ 2 rows in set (0.00 sec
7.3恢复192.168.3.81节点1mysql服务，及查询节点1数据是否正常。
[root@M1905 ~]# service mysql start Starting MySQL (Percona XtraDB Cluster).... SUCCESS! [root@M1905 ~]# mysql -u root -p123456 -S /tmp/mysql.sock mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | liu | | log | | mysql | | performance_schema | | test | +--------------------+ 6 rows in set (0.00 sec) mysql> use liu Database changed mysql> select * from liu01; +------+------+ | id | name | +------+------+ | 1 | aa | | 2 | bb | +------+------+ 2 rows in set (0.00 sec)
mysql> show global status like ‘wsrep%‘; +------------------------------+-------------------------------------------------------+ | Variable_name | Value | +------------------------------+-------------------------------------------------------+ | wsrep_local_state_uuid | fdfec3ab-d9e8-11e4-94aa-ae45256a81fb | | wsrep_protocol_version | 7 | | wsrep_last_committed | 8 | | wsrep_replicated | 0 | | wsrep_replicated_bytes | 0 | | wsrep_repl_keys | 0 | | wsrep_repl_keys_bytes | 0 | | wsrep_repl_data_bytes | 0 | | wsrep_repl_other_bytes | 0 | | wsrep_received | 3 | | wsrep_received_bytes | 287 | | wsrep_local_commits | 0 | | wsrep_local_cert_failures | 0 | | wsrep_local_replays | 0 | | wsrep_local_send_queue | 0 | | wsrep_local_send_queue_max | 1 | | wsrep_local_send_queue_min | 0 | | wsrep_local_send_queue_avg | 0.000000 | | wsrep_local_recv_queue | 0 | | wsrep_local_recv_queue_max | 1 | | wsrep_local_recv_queue_min | 0 | | wsrep_local_recv_queue_avg | 0.000000 | | wsrep_local_cached_downto | 0 | | wsrep_flow_control_paused_ns | 0 | | wsrep_flow_control_paused | 0.000000 | | wsrep_flow_control_sent | 0 | | wsrep_flow_control_recv | 0 | | wsrep_cert_deps_distance | 0.000000 | | wsrep_apply_oooe | 0.000000 | | wsrep_apply_oool | 0.000000 | | wsrep_apply_window | 1.000000 | | wsrep_commit_oooe | 0.000000 | | wsrep_commit_oool | 0.000000 | | wsrep_commit_window | 1.000000 | | wsrep_local_state | 4 | | wsrep_local_state_comment | Synced | | wsrep_cert_index_size | 0 | | wsrep_causal_reads | 0 | | wsrep_cert_interval | 0.000000 | | wsrep_incoming_addresses | 192.168.3.82:3306,192.168.3.81:3306,192.168.3.83:3306 | | wsrep_evs_delayed | | | wsrep_evs_evict_list | | | wsrep_evs_repl_latency | 0/0/0/0/0 | | wsrep_evs_state | OPERATIONAL | | wsrep_gcomm_uuid | 4be90b42-dccf-11e4-83f4-5238aff4e818 | | wsrep_cluster_conf_id | 5 | | wsrep_cluster_size | 3 | | wsrep_cluster_state_uuid | fdfec3ab-d9e8-11e4-94aa-ae45256a81fb | | wsrep_cluster_status | Primary | | wsrep_connected | ON | | wsrep_local_bf_aborts | 0 | | wsrep_local_index | 1 | | wsrep_provider_name | Galera | | wsrep_provider_vendor | Codership Oy <info@codership.com> | | wsrep_provider_version | 3.9(r93aca2d) | | wsrep_ready | ON | +------------------------------+-------------------------------------------------------+
发现wsrep_incoming_addresses的192.168.3.81:3306已经存在，并且wsrep_cluster_size可用节点为3.
8.感觉"Percona XtraDB cluster“的高可用增加删除节点很方便，自动切换故障，如果能配合atlas做读写分离就完美了，但是经过测试,cluster写性能真的不咋的，如果对写要求不高，还是不错的选择。
本文出自 “从心开始” 博客，请务必保留此出处http://hao360.blog.51cto.com/5820068/1674062
Percona XtraDB Cluster 5.6安装配置
原文地址：http://hao360.blog.51cto.com/5820068/1674062
