The document discusses Galera replication, which uses write set replication and global transaction IDs to synchronize data across multiple MySQL nodes. It describes how Galera is implemented using the WSREP plugin to backup data, generate transaction IDs, and certify write sets between nodes. The key steps for setting up Galera replication are also summarized, including configuring MySQL, performing an initial sync, adding new nodes, and setting up an arbitrator.

1. GaleraGalera
Master-MasterMaster-Master
ReplicationReplication
Marian HackMan Marinov <mm@1h.com>

2. What is the BinaryLog?
UPDATE t1 SET count=100 WHERE id=100UPDATE t1 SET count=100 WHERE id=100
CLIENTCLIENT

3. What is the BinaryLog?
UPDATE t1 SET count=100 WHERE id=100UPDATE t1 SET count=100 WHERE id=100
CLIENTCLIENT

4. What is the BinaryLog?
UPDATE t1 SET count=100 WHERE id=100UPDATE t1 SET count=100 WHERE id=100
CLIENTCLIENT
SUCCESS

5. What is the BinaryLog?
UPDATE t1 SET count=100 WHERE id=100UPDATE t1 SET count=100 WHERE id=100
CLIENTCLIENT
SUCCESS

6. Types of Replication
● STATEMENT
● ROW
● MIXED
● Master-Slave
● Master-Master

7. Types of Replication
● STATEMENT
UPDATE t1 SET count=100 WHERE id=100;UPDATE t1 SET count=100 WHERE id=100;
INSERT INTO t1 VALUES (102, 1);INSERT INTO t1 VALUES (102, 1);

8. Types of Replication
● ROW
table t1 change:table t1 change:
ROW id=100 count=100ROW id=100 count=100
table t1 change:table t1 change:
add row with id=102, count=1add row with id=102, count=1

9. Types of Replication
● MIXED
UPDATE t1 SET count=100 WHERE id=100;UPDATE t1 SET count=100 WHERE id=100;
table t1 change:table t1 change:
ROW id=100 count=100ROW id=100 count=100
INSERT INTO t1 VALUES (102, 1);INSERT INTO t1 VALUES (102, 1);
table t1 change:table t1 change:
add row with id=102, count=1add row with id=102, count=1

10. What is Galera
●
Write set replication - WSREPWrite set replication - WSREP
●
Global Transaction ID - GTIDGlobal Transaction ID - GTID

11. What is Galera
●
Write set replication - WSREPWrite set replication - WSREP
UPDATE t1 SET count=100 WHERE id=100;UPDATE t1 SET count=100 WHERE id=100;
INSERT INTO t1 VALUES (102, 1);INSERT INTO t1 VALUES (102, 1);
Write setWrite set

12. What is Galera
●
Write set replication - WSREPWrite set replication - WSREP
UPDATE t1 SET count=100 WHERE id=100;UPDATE t1 SET count=100 WHERE id=100;
INSERT INTO t1 VALUES (102, 1);INSERT INTO t1 VALUES (102, 1);
Write setWrite set
GTID: 318e70bb-4ba2-4707-aa5f-20cf44c3d367GTID: 318e70bb-4ba2-4707-aa5f-20cf44c3d367

13. What is Galera
●
Write set replication - WSREPWrite set replication - WSREP
UPDATE t1 SET count=100 WHERE id=100;UPDATE t1 SET count=100 WHERE id=100;
INSERT INTO t1 VALUES (102, 1);INSERT INTO t1 VALUES (102, 1);
Write setWrite set
GTID: 318e70bb-4ba2-4707-aa5f-20cf44c3d367GTID: 318e70bb-4ba2-4707-aa5f-20cf44c3d367
Certification based replication???Certification based replication???

14. ● WSREP XXX-XXX
– certificate that it can proceed
– check based on table's primary key

15. How is it implemented?

16. How is it implemented?

17. How is it implemented?
● WSREP plugin
– backing up data
● logs and files
– conns between nodes
– generating GTIDs
– certification of WSETs
WSREP

18. How is it implemented?

19. Node states

20. ● State Snapshot Transfer (SST)
– Logical - mysqldump
– Physical
● rsync/rsync_wan
● xtrabackup
wsrep_sst_method=xtrabackupv2
● Incremental State Transfer (IST)
5a76ef62-30ec-11e1-0800-dba504cf2aab:197222
5a76ef62-30ec-11e1-0800-dba504cf2aab:201913
– Write-set cache (GCache)

21. Requirements
● binlog_format=ROW
● Storage engine InnoDB/XtraDB
● All tables should have a primary key

22. Setup
/etc/yum.repos.d/galera.repo
[galera]
name = Galera
baseurl =
http://releases.galeracluster.com/centos/6/x86_64
gpgkey = http://releases.galeracluster.com/GPG-
KEY-galeracluster.com
gpgcheck = 1

23. Setup
yum install
Percona-XtraDB-Cluster-server
Percona-XtraDB-Cluster-client
Percona-XtraDB-Cluster-galera-3.x86_64
galera
socat
pv
pigz
nc

24. Setup
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=mysql
binlog_format=ROW
bind-address=0.0.0.0
default_storage_engine=innodb
innodb_autoinc_lock_mode=2
innodb_flush_log_at_trx_commit=0
innodb_buffer_pool_size=122M

25. Setup
wsrep_provider=/usr/lib64/galera3/libgalera_smm.so
wsrep_provider_options="gcache.size=300M;gcache.p
age_size=300M"
wsrep_cluster_name="example_cluster"
wsrep_cluster_address="gcomm://10.19.1.8,10.19.1.9"
wsrep_sst_method=xtrabackup-v2
wsrep_sst_auth="root:ensurethehighest"

26. Setup
[sst]
progress=/var/log/mysql/sst.log
streamfmt=xbstream
transferfmt=socat
encrypt=2
encrypt-algo=AES256
tkey=/etc/mysql/key.pem
tcert=/etc/mysql/cert.pem
compressor="pigz -6"
decompressor="pigz -d"

27. First start
# mysql_install_db
# service mysql start --wsrep-new-cluster

28. Adding new node
● Add GRANTs for the new machine
– GRANT ALL ON *.* TO 'root'@'10.19.1.10' IDENTIFIED BY 'ensurethehighest';
● Copy the my.cnf from another node
● Fix the node_name and node_address
● Add the IP of the local node to cluster_address
● Start MySQL on the new node
● After the sync is done and the new node is in the cluster
– update the cluster_address in the configuration of the other nodes
– update the cluster_address in the running mysql instances:
mysql> set global wsrep_cluster_address =
'gcomm://10.19.1.8,10.19.1.9,10.19.1.10';

29. Arbitrator
# chkconfig garb on
# cat /etc/sysconfig/garb
GALERA_NODES="10.19.1.8:4567
10.19.1.9:4567 10.19.1.10:4567"
GALERA_GROUP="gp_cluster"
# /etc/init.d/garb restart

30. QUESTIONS???QUESTIONS???
Marian HackMan Marinov <mm@1h.com>