Download as PDF, PPTX
![Lab 2: Install PXC on node3
Install PerconaXtraDBCluster
server56
Edit my.cnf to have the mandatory PXC
settings
node3
PXC
Handson!
[mysqld]
binlog_format=ROW
wsrep_provider=/usr/lib/libgalera_smm.so
wsrep_cluster_address=gcomm://192.168.70.3
wsrep_node_address=192.168.70.3
wsrep_cluster_name=Pluk2k13
wsrep_node_name=node3
innodb_autoinc_lock_mode=2](https://image.slidesharecdn.com/pxctutorialpluk2k14-160520082302/85/Percon-XtraDB-Cluster-in-a-nutshell-50-320.jpg)
![Lab 2: It's time for some extra work ! Handson!
It's always better to have a specific user to use
with xtrabackup (we will use it later for SST too)
Even if you use the default datadir in MySQL,
it's mandatory to add it in my.cnf
node1 mysql> GRANT reload, lock tables, replication client ON
*.* TO 'sst'@'localhost' IDENTIFIED BY 'sst';
datadir=/var/lib/mysl
[xtrabackup]
user=sst
password=sst](https://image.slidesharecdn.com/pxctutorialpluk2k14-160520082302/85/Percon-XtraDB-Cluster-in-a-nutshell-53-320.jpg)
![Lab 2: configuration for replication Handson!
[mysqld]
binlog_format=ROW
log_slave_updates
wsrep_provider=/usr/lib/libgalera_smm.so
wsrep_cluster_address=gcomm://192.168.70.3
wsrep_node_address=192.168.70.3
wsrep_cluster_name=Pluk2k13
wsrep_node_name=node3
wsrep_slave_threads=2
wsrep_sst_method=xtrabackupv2
wsrep_sst_auth=sst:sst
innodb_autoinc_lock_mode=2
innodb_file_per_table
gtid_mode=on
enforce_gtid_consistency
skip_slave_start
serverid=3
log_bin=mysqlbin
datadir=/var/lib/mysql
[xtrabackup]
user=sst
password=sst](https://image.slidesharecdn.com/pxctutorialpluk2k14-160520082302/85/Percon-XtraDB-Cluster-in-a-nutshell-56-320.jpg)
![Lab 3: migrate 5.6 slave to PXC (step 3)
Install PXC on node2
Configure it
Start it (don't bootstrap it !)
Check the mysql logs on both
PXC nodes
node2
PXC
node3
PXC
slave
Handson!
wsrep_cluster_address=gcomm://192.168.70.2,192.168.70.3
wsrep_node_address=192.168.70.2
wsrep_node_name=node2
[...]](https://image.slidesharecdn.com/pxctutorialpluk2k14-160520082302/85/Percon-XtraDB-Cluster-in-a-nutshell-59-320.jpg)
![Lab 3: migrate 5.6 slave to PXC (step 3)
Install PXC on node2
Configure it
Start it (don't bootstrap it !)
Check the mysql logs on both
PXC nodes
node2
PXC
node3
PXC
slave
Handson!
wsrep_cluster_address=gcomm://192.168.70.2,192.168.70.3
wsrep_node_address=192.168.70.2
wsrep_node_name=node2
[...]
Did you disable selinux ??
setenforce 0](https://image.slidesharecdn.com/pxctutorialpluk2k14-160520082302/85/Percon-XtraDB-Cluster-in-a-nutshell-60-320.jpg)
![Lab 3: migrate 5.6 slave to PXC (step 3)
Install PXC on node2
Configure it
Start it (don't bootstrap it !)
Check the mysql logs on both
PXC nodes
node2
PXC
node3
PXC
slave
Handson!
wsrep_cluster_address=gcomm://192.168.70.2,192.168.70.3
wsrep_node_address=192.168.70.2
wsrep_node_name=node2
[...]
on node3 (the donor) tail the file innobackup.backup.log in datadir
on node 2 (the joiner) as soon as created check the file innobackup.prepare.log](https://image.slidesharecdn.com/pxctutorialpluk2k14-160520082302/85/Percon-XtraDB-Cluster-in-a-nutshell-61-320.jpg)
![Lab 3: migrate 5.6 slave to PXC (step 3)
Install PXC on node2
Configure it
Start it (don't bootstrap it !)
Check the mysql logs on both
PXC nodes
node2
PXC
node3
PXC
slave
Handson!
wsrep_cluster_address=gcomm://192.168.70.2,192.168.70.3
wsrep_node_address=192.168.70.2
wsrep_node_name=node2
[...]
we can check on one of the nodes if the cluster
is indeed running with two nodes:
mysql> show global status like 'wsrep_cluster_size';
+++
| Variable_name | Value |
+++
| wsrep_cluster_size | 2 |
+++](https://image.slidesharecdn.com/pxctutorialpluk2k14-160520082302/85/Percon-XtraDB-Cluster-in-a-nutshell-62-320.jpg)
![Lab 4: Xtrabackup & xbstream
as SST (step 4)
Migrate the master to PXC
Configure SST to use Xtrabackup with 2
threads and compression
[mysqld]
wsrep_sst_method=xtrabackupv2
wsrep_sst_auth=sst:sst
[xtrabackup]
compress
parallel=2
compressthreads=2
[sst]
streamfmt=xbstream
Handson!
qpress needs to be
installed on all nodes
don't forget to stop & reset async slave](https://image.slidesharecdn.com/pxctutorialpluk2k14-160520082302/85/Percon-XtraDB-Cluster-in-a-nutshell-70-320.jpg)
Uploaded byFrederic Descamps
Percon XtraDB Cluster in a nutshell
The document is a hands-on tutorial on the Percona XtraDB Cluster, covering essential topics such as migration from a master/slave setup, Galera replication concepts, and application interaction. It also includes detailed steps for setting up, configuring, and migrating to the XtraDB Cluster, highlighting the differences between synchronous and asynchronous replication. Limitations and best practices for optimizing the use of the cluster are shared throughout the tutorial.
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Percon XtraDB Cluster in a nutshell
- 1. Percona XtraDB Clusterin a nutshell Hands-on tutorial Liz van Dijk Kenny Gryp Frédéric Descamps 3 Nov 2014
- 2. Percona XtraDB Clusterin a nutshell Hands-on tutorial Liz van Dijk Kenny Gryp Frédéric Descamps 3 Nov 2014
- 3. Who are we? • Frédéric Descamps • @lefred • Senior Architect • devops believer • Percona Consultant since 2011 • Managing MySQL since 3.23 (as far as I remember) • http://about.me/lefred • Kenny Gryp • @gryp • Principal Architect • Kali Dal expert • Kheer master • Naan believer • Paratha Consultant since 2012 • Liz van Dijk • @lizztheblizz •
- 4. Agenda PXC and galerareplication concepts Migrating a master/slave setup State transfer Config / schema changes Application interaction Advanced Topics 4
- 5. Percona • We arethe oldest and largest independent MySQL Support, Consulting, Remote DBA, Training, and Software Development company with a global, 24x7 staff of nearly 100 serving more than 2,000 customers in 50+ countries since 2006 ! • Our contributions to the MySQL community include open source server and tools software, books, and original research published on the Percona's Blog 5
- 6. Get more afterthe tutorial Synchronous Revelation, Alexey Yurchenko, 9:40am - 10:05am Moving a MySQL infrastructure with 130K QPS to Galera, Walther Heck, 2:10pm – 3.00pm @ Cromwell 1&2 Galera Cluster New Features, Seppo Jaakola, 3:10pm – 4:00pm @ Cromwell 3&4 15 Tips to Boost your Galera Cluster, lefred, 5:30pm – 6:20pm @ Cromwell 1&2
- 7.
- 8. Traditional Replication Approach Server-centric: “one server streams data to another” 8 Server 1 Server 2 replication stream “master” “slave”
- 9. This can leadto cool topologies ! 9 1 2 3 4 5 6 7 8 9 10 1213 14 15 16 17 18 19 11
- 10. Galera (wsrep) Approach 10 DATA Server 1Server 2 Server 3 Server N... The dataset is synchronized between one or more servers: data-centric
- 11. Galera (wsrep) Approach 11 DATA Server 1Server 2 Server 3 Server N... The dataset is synchronized between one or more servers: data-centric So database filters are not supported !!
- 12. Multi-Master Replication • Youcan write to any node in your cluster • Don't worry about eventual out-of-sync 12 writes writes writes
- 13. Parallel Replication • PXC/ Galera 13 Writes N threads Apply M threads
- 14. Understanding Galera 14 The clustercan be seen as a meeting !
- 15. PXC (Galera cluster)is a meeting 15 bfb912e5-f560-11e2-0800-1eefab05e57d
- 16. PXC (Galera cluster)is a meeting 16 bfb912e5-f560-11e2-0800-1eefab05e57d
- 17. PXC (Galera cluster)is a meeting 17 bfb912e5-f560-11e2-0800-1eefab05e57d
- 18. PXC (Galera cluster)is a meeting 18 bfb912e5-f560-11e2-0800-1eefab05e57d
- 19. PXC (Galera cluster)is a meeting 19 bfb912e5-f560-11e2-0800-1eefab05e57d
- 20. PXC (Galera cluster)is a meeting 20 bfb912e5-f560-11e2-0800-1eefab05e57d
- 21. PXC (Galera cluster)is a meeting 21 bfb912e5-f560-11e2-0800-1eefab05e57d
- 22. PXC (Galera cluster)is a meeting 22 bfb912e5-f560-11e2-0800-1eefab05e57d Only one node remaining but as all the others left gracefully, we still have a meeting !
- 23. PXC (Galera cluster)is a meeting 23
- 24. PXC (Galera cluster)is a meeting 24 ???
- 25. PXC (Galera cluster)is a meeting 25 4fd8824d-ad5b-11e2-0800-73d6929be5cf New meeting !
- 26.
- 27. Lab 1: preparethe VM's Handson! Copy all .zip files from USB stick to your machine Uncompress them and double click on each *.vbox files (ex: PLUK 2k14 node1 (32bit).box) Start all virtual machines (app, node1, node2 and node3) Install putty if you are using Windows
- 28. Lab 1: testconnectivity Handson! Try to connect to all VM's from a terminal or putty ssh p 2221 root@127.0.0.1 to node1 ssh p 2222 root@127.0.0.1 to node2 ssh p 2223 root@127.0.0.1 to node3 ssh p 2224 root@127.0.0.1 to app root password is “vagrant” !
- 29. Lab 1: everybodyOK ? Handson!
- 30. Lab 1: YES!! Handson!
- 31. Lab 1: currentsituation Handson! app node1 master node2 slave node3 spare asynchronous replication
- 32. Lab 1: currentsituation Handson! app node1 master node2 slave node3 spare asynchronous replication please start replication on node2 when it's booted if needed: mysql> start slave;
- 33. Lab 1: systemsummary Handson! app node1 node2 node3 current role application server master slave spare root pwd vagrant vagrant vagrant vagrant ssh port 2221 2222 2223 2224 internal IP 192.168.70.4 192.168.70 .1 192.168.70.2 192.168.70.3
- 34. Is PXC Goodfor me?
- 35. (Virtual) Synchronous Replication •Different from asynchronous MySQL replication: – Writesets (tx) are replicated to all available nodes on commit (and en-queued on each) – Writesets are individually “certified” on every node, determinsitically. – Queued writesets are applied on those nodes independently and asynchronously – Flow Control avoids too much “lag”. 35
- 36. Limitations Supports only InnoDBtables – MyISAM support is very basic and will stay in alpha. Different locking: optimistic locking The weakest node limits the write performance For write intensive applications there could be datasize limit per node All tables should have a Primary Key !
- 37. Limitations Supports only InnoDBtables – MyISAM support is very basic and will stay in alpha. Different locking: optimistic locking The weakest node limits the write performance For write intensive applications there could be datasize limit per node All tables should have a Primary Key ! wsrep_certify_nonPK=1 can now deal with non PK, but it's still not recommended to use tables without PK !
- 38. Limitations (2) Large transactionsare not recommended if you write on all nodes simultaneously If your application has a data hotspot then PXC may not be right for you. By default a writeset can contain maximum 128k rows and limited to 1G
- 39. Limitations (2) Large transactionsare not recommended if you write on all nodes simultaneously If your application has a data hotspot then PXC may not be right for you. By default a writeset can contain maximum 128k rows and limited to 1GThis is defined by wsrep_max_ws_rows and wsrep_max_ws_size
- 40. OPTIMISTIC locking fortransactions on different servers Traditional locking system 1 Transaction 1 Transaction 2 BEGIN Transaction1 BEGIN UPDATE t WHERE id=14 UPDATE t WHERE id=14 ... COMMIT Waits on COMMIT in trx 1
- 41. OPTIMISTIC locking fortransactions on different servers Optimistic locking system 1 Transaction 1 Transaction 2 BEGIN Transaction1 BEGIN UPDATE t WHERE id=14 UPDATE t WHERE id=14 ... COMMIT system 2 ... COMMIT ERROR due row conflict
- 42. OPTIMISTIC locking fortransactions on different servers Optimistic locking system 1 Transaction 1 Transaction 2 BEGIN Transaction1 BEGIN UPDATE t WHERE id=14 UPDATE t WHERE id=14 ... COMMIT system 2 ... COMMIT ERROR due row conflict ERROR 1213 (40001): Deadlock found when trying to get lock; try restarting transaction
- 43. Summary Make sure youhave no long running transactions – They can stall replication Make sure you have no data hot spots – They are not locks waits, but rollbacks if coming from different nodes
- 44.
- 45. What's the plan? app node1 master node2 slave node3 spare asynchronous replication Current Situation
- 46. What's the plan? app node1 master node2 slave node3 PXC asynchronous replication Step 1: install PXC
- 47. What's the plan? app node1 master node2 slave node3 PXC slave asynchronous replication Step 2: setup PXC as async slave asynchronous replication asynchronous replication
- 48. What's the plan? app node1 master node2 PXC node3 PXC slave Step 3: migrate slave to PXC asynchronous replication
- 49. What's the plan? app node1 PXC node2 PXC node3 PXC slave Step 4: migrate master to PXC
- 50. Lab 2: InstallPXC on node3 Install PerconaXtraDBCluster server56 Edit my.cnf to have the mandatory PXC settings node3 PXC Handson! [mysqld] binlog_format=ROW wsrep_provider=/usr/lib/libgalera_smm.so wsrep_cluster_address=gcomm://192.168.70.3 wsrep_node_address=192.168.70.3 wsrep_cluster_name=Pluk2k13 wsrep_node_name=node3 innodb_autoinc_lock_mode=2
- 51. Step 2: setupthat single node cluster as asynchronous slave We need to verify if the configuration is ready for that Make a slave Bootstrap our single node Percona XtraDB Cluster Start replication.... we use 5.6 with GTID! Disable selinux on all boxes ! – setenforce 0
- 52. Lab 2: let'smake a slave ! Handson! We need to take a backup (while production is running) We need to restore the backup We need to add requested grants We need to configure our PXC node to use GTID We need to see a bit longer and prepare that new slave to spread all the replicated events to the future cluster nodes
- 53. Lab 2: It'stime for some extra work ! Handson! It's always better to have a specific user to use with xtrabackup (we will use it later for SST too) Even if you use the default datadir in MySQL, it's mandatory to add it in my.cnf node1 mysql> GRANT reload, lock tables, replication client ON *.* TO 'sst'@'localhost' IDENTIFIED BY 'sst'; datadir=/var/lib/mysl [xtrabackup] user=sst password=sst
- 54. Lab 2: backupand restore Handson! node3# /etc/init.d/mysql stop node3# cd /var/lib/mysql; rm rf * node3# nc l 9999 | tar xvmfi node1# innobackupex stream=tar /tmp | nc 192.168.70.3 9999 node3# innobackupex applylog . node3# chown R mysql. /var/lib/mysql node1 mysql> GRANT REPLICATION SLAVE ON *.* TO 'repl'@'192.168.70.3' IDENTIFIED BY 'pluk';
- 55. Lab 2: backupand restore Handson! node3# /etc/init.d/mysql stop node3# cd /var/lib/mysql; rm rf * node3# nc l 9999 | tar xvmfi node1# innobackupex stream=tar /tmp | nc 192.168.70.3 9999 node3# innobackupex applylog . node3# chown R mysql. /var/lib/mysql node1 mysql> GRANT REPLICATION SLAVE ON *.* TO 'repl'@'192.168.70.3' IDENTIFIED BY 'pluk'; we need to know the last GTID purged, check in /var/lib/mysql/xtrabackup_binlog_info
- 56. Lab 2: configurationfor replication Handson! [mysqld] binlog_format=ROW log_slave_updates wsrep_provider=/usr/lib/libgalera_smm.so wsrep_cluster_address=gcomm://192.168.70.3 wsrep_node_address=192.168.70.3 wsrep_cluster_name=Pluk2k13 wsrep_node_name=node3 wsrep_slave_threads=2 wsrep_sst_method=xtrabackupv2 wsrep_sst_auth=sst:sst innodb_autoinc_lock_mode=2 innodb_file_per_table gtid_mode=on enforce_gtid_consistency skip_slave_start serverid=3 log_bin=mysqlbin datadir=/var/lib/mysql [xtrabackup] user=sst password=sst
- 57. Lab 2: bootstrapthe cluster and start replication Handson! # /etc/init.d/mysql bootstrappxc To bootstrap the cluster, you need to use bootstrappxc as command for init script Setup replication node3 mysql> CHANGE MASTER TO MASTER_HOST ='192.168.70.1', MASTER_USER ='repl', MASTER_PASSWORD = 'pluk', MASTER_AUTO_POSITION =1; node3 mysql> set global gtid_purged="..."; node3 mysql> START SLAVE;
- 58. Lab 2: bootstrapthe cluster and start replication Handson! # /etc/init.d/mysql bootstrappxc To bootstrap the cluster, you need to use bootstrappxc as command for init script Setup replication node3 mysql> CHANGE MASTER TO MASTER_HOST ='192.168.70.1', MASTER_USER ='repl', MASTER_PASSWORD = 'pluk', MASTER_AUTO_POSITION =1; node3 mysql> set global gtid_purged="..."; node3 mysql> START SLAVE; Did you disable selinux ?? setenforce 0
- 59. Lab 3: migrate5.6 slave to PXC (step 3) Install PXC on node2 Configure it Start it (don't bootstrap it !) Check the mysql logs on both PXC nodes node2 PXC node3 PXC slave Handson! wsrep_cluster_address=gcomm://192.168.70.2,192.168.70.3 wsrep_node_address=192.168.70.2 wsrep_node_name=node2 [...]
- 60. Lab 3: migrate5.6 slave to PXC (step 3) Install PXC on node2 Configure it Start it (don't bootstrap it !) Check the mysql logs on both PXC nodes node2 PXC node3 PXC slave Handson! wsrep_cluster_address=gcomm://192.168.70.2,192.168.70.3 wsrep_node_address=192.168.70.2 wsrep_node_name=node2 [...] Did you disable selinux ?? setenforce 0
- 61. Lab 3: migrate5.6 slave to PXC (step 3) Install PXC on node2 Configure it Start it (don't bootstrap it !) Check the mysql logs on both PXC nodes node2 PXC node3 PXC slave Handson! wsrep_cluster_address=gcomm://192.168.70.2,192.168.70.3 wsrep_node_address=192.168.70.2 wsrep_node_name=node2 [...] on node3 (the donor) tail the file innobackup.backup.log in datadir on node 2 (the joiner) as soon as created check the file innobackup.prepare.log
- 62. Lab 3: migrate5.6 slave to PXC (step 3) Install PXC on node2 Configure it Start it (don't bootstrap it !) Check the mysql logs on both PXC nodes node2 PXC node3 PXC slave Handson! wsrep_cluster_address=gcomm://192.168.70.2,192.168.70.3 wsrep_node_address=192.168.70.2 wsrep_node_name=node2 [...] we can check on one of the nodes if the cluster is indeed running with two nodes: mysql> show global status like 'wsrep_cluster_size'; +++ | Variable_name | Value | +++ | wsrep_cluster_size | 2 | +++
- 63. StateTransfer Summary 75 Full data SST Incremental IST Newnode Node long time disconnected Node disconnected short time
- 64. Snapshot State Transfer 76 mysqldump Small databases rsync Donor disconnected forcopy time Faster XtraBackup Donor available Slower
- 65. Incremental State Transfer 77 Nodewas in the cluster Disconnected for maintenance Node crashed
- 66. Automatic Node Provisioning 78 writes writes writes newnode joining data is copied via SST or IST
- 67. Automatic Node Provisioning 79 writes writes writes newnode joiningwhen ready writes
- 68.
- 69. XtraBackup as SST XtraBackupas SST now supports xbstream format. This allows: – Xtrabackup in parallel – Compression – Compact format – Encryption
- 70. Lab 4: Xtrabackup& xbstream as SST (step 4) Migrate the master to PXC Configure SST to use Xtrabackup with 2 threads and compression [mysqld] wsrep_sst_method=xtrabackupv2 wsrep_sst_auth=sst:sst [xtrabackup] compress parallel=2 compressthreads=2 [sst] streamfmt=xbstream Handson! qpress needs to be installed on all nodes don't forget to stop & reset async slave
- 71. Using a loadbalancer
- 72. PXC with aLoad balancer • PXC can be integrate with a load balancer and service can be checked using clustercheck or pyclustercheck • The load balancer can be a dedicated one • or integrated on each application servers 84
- 73. Dedicated shared HAProxy applicationserver 1 application server 2 application server 3 PXC node 1 PXC node 2 PXC node 3 HA PROXY
- 74. Dedicated shared HAProxy applicationserver 1 application server 2 application server 3 PXC node 1 PXC node 2 PXC node 3 HA PROXY
- 75. Dedicated shared HAProxy applicationserver 1 application server 2 application server 3 PXC node 1 PXC node 2 PXC node 3 HA PROXY SST available_when_donor=0
- 76.
- 77. Lab 5: PXCand Load Balancer Handson! Intsall xinetd and configure mysqchk on all nodes Test that it works using curl Install HA Proxy (haproxy.i686) on app and start it Connect on port 3306 several times on app, what do you see? Connect on port 3307 several times, what do you see ? Modify runapp.sh to point to 192.168.70.4, run it... Check the HA proxy frontend (http://127.0.0.1:8081/haproxy/stats) Stop xinetd on the node getting the writes, what do you see ? haproxy's configuration file is /etc/haproxy/haproxy.cfg
- 78.
- 79. Base setup app PXC node1 PXC node 2 PXC node 3 HA PROXY
- 80. Remove 1st node app PXCnode 1 PXC node 2 PXC node 3 HA PROXY Change the configuration and put it back in
- 81. Remove 2nd node app PXCnode 1 PXC node 2 PXC node 3 HA PROXY Change the configuration and put it back in
- 82. Remove 3rd node app PXCnode 1 PXC node 2 PXC node 3 HA PROXY Change the configuration and put it back in
- 83. Lab 6: Configurationchanges Handson! Set wsrep_slave_threads=4 on all nodes without bringing down the whole cluster. Make sure that the backend is down in haproxy. Hint: # service xinetd stop … do the change ... # service xinetd start
- 84. Schema changes: pt-online-shema-change Doesthe work in chunks Everything is done in small transactions, which counts as a good workload It can't modify tables with triggers It's slower than 5.6 online DDL
- 85. Schema changes: 5.6'sALTER It can be lockless, but it will be a large transcation which has to replicate Most likely it will cause a stall because of that. If the change is RBR compatible, it can be done on a node by node basis. if the transaction is not too large, with 5.6 always try an alter statement with lock=NONE and if it fails, then use ptosc
- 86. Schema changes: RSU(rolling schema upgrade) PXC's built-in solution Puts the node into desync node during the alter. ALTER the nodes one by one Set using wsrep_OSU_method
- 87. Finer control foradvanced users Since PXC 5.5.33-23.7.6 you can manage your DDL (data definition language) you can proceed as follow: mysql> SET GLOBAL wsrep_desync=ON; mysql> SET wsrep_on=OFF; ... DDL (optimize, add index, rebuild, etc.) ... mysql> SET wsrep_on=ON; mysql> SET GLOBAL wsrep_desync=OFF This is tricky and risky, try to avoid ;-)
- 88. Finer control foradvanced users Since PXC 5.5.33-23.7.6 you can manage your DDL (data definition language) you can proceed as follow: mysql> SET GLOBAL wsrep_desync=ON; mysql> SET wsrep_on=OFF; ... DDL (optimize, add index, rebuild, etc.) ... mysql> SET wsrep_on=ON; mysql> SET GLOBAL wsrep_desync=OFF this allows the node to fall behind the cluster
- 89. Finer control foradvanced users Since PXC 5.5.33-23.7.6 you can manage your DDL (data definition language) you can proceed as follow: mysql> SET GLOBAL wsrep_desync=ON; mysql> SET wsrep_on=OFF; ... DDL (optimize, add index, rebuild, etc.) ... mysql> SET wsrep_on=ON; mysql> SET GLOBAL wsrep_desync=OFF this disables replication for the given session
- 90. myq_gadgets During the restof the day we will use myq_status to monitor our cluster Command line utility part of myq_gadgets Written by Jay Janssen - https://github.com/jayjanssen/myq_gadgets
- 91. Lab 7: Schemachanges Handson! Do the following schema change. – With regular ALTER – With pt-online-schema-change – With RSU – With 5.6's online ALTER ALTER TABLE sbtest.sbtest1 ADD COLUMN d VARCHAR(5); ALTER TABLE sbtest.sbtest1 DROP COLUMN d; make sure sysbench is running and don't forget to examine myq_status
- 92.
- 93. PXC manages Quorum Ifa node does not see more than 50% of the total amount of nodes: reads/writes are not accepted. Split brain is prevented This requires at least 3 nodes to be effective a node can be an arbitrator (garbd), joining the communication, but not having any MySQL running Can be disabled (but be warned!) You can cheat and play with node weight
- 94. Quorum: lost ofconnectivity
- 95. Quorum: lost ofconnectivity Network Problem
- 96. Quorum: lost ofconnectivity Network Problem Does not accept Reads & Writes
- 97. Quorum: even numberof nodes !!
- 98. Quorum: even numberof nodes !! Network Problem
- 99. Quorum: even numberof nodes !! Network Problem
- 100. Quorum: even numberof nodes !! Network Problem is 2 bigger than 50% ?
- 101. This is toavoid split-brain !! Network Problem no it's NOT !! FIGHT !!
- 102. Cheat with nodesweight for quorum You can define the weight of a node to affect the quorum calculation using the galera parameter pc.weight (default is 1)
- 103. Lab 8: Breakingthings Handson! Start sysbench through the load balancer. Stop 1 node gracefully. Stop 2 nodes gracefully. Start all nodes. Crash 1 node. Crash an other node. Hint: # service mysql stop # echo c > /proc/sysrqtrigger
- 104.
- 105.
- 106. Asynchronous slave II. app node1 PXC node2 PXC node3 PXC Ifthe node crashes, the async slave won't get the updates.
- 107.
- 108.
- 109. Lab 9: Asynchronousreplication Handson! Prepare the cluster for this lab – nothing to do as we use xtrabackup >= 2.1.7 ;-) Make sure some sysbench workload is running through some haproxy before xtrabackup 2.1.7, rsync was the only sst method supporting the copy of binary logs
- 110. Lab 9: Asynchronousreplication Handson! Install Percona Server 5.6 on app and make it a slave Set the port to 3310 (because haproxy) Crash node 1 Reposition replication to node 2 or 3 CHANGE MASTER TO MASTER_HOST='192.168.70.2', MASTER_USER='repl', MASTER_PASSWORD='pluk', MASTER_AUTO_POSITION=1; # echo c > /proc/sysrqtrigger
- 111.
- 112. WAN replication MySQL MySQL MySQL Works fine Usehigher timeouts and send windows No impact on reads No impact within a transaction Increase commit latency
- 113. WAN replication -latencies MySQL MySQL MySQL Beware of latencies Within EUROPE EC2 – INSERT INTO table: 0.005100 sec EUROPE <-> JAPAN EC2 – INSERT INTO table: 0.275642 sec
- 114. WAN replication withMySQL asynchronous replication MySQL MySQL MySQL You can mix both replications Good option on slow WAN link Requires more nodes If binlog position is lost, full cluster must be reprovisioned MySQL MySQL MySQL MySQL MySQL MySQL
- 115. Better WAN Replicationwith Galera 3.0 Galera 3.0's replication mode is optimized for high latency networks Uses cluster segments
- 116. Wan Replication 2.0 datacenterA datacenter B
- 117. Wan Replication 2.0 datacenterA datacenter B It requires all point-to-point connections for replication
- 118. Wan Replication 2.0 datacenterA datacenter B ALL !!
- 119. Wan Replication 3.0 datacenterA datacenter B Replication between cluster segments go over one link only
- 120. Wan Replication 3.0 datacenterA datacenter B Segments gateways can change per transactions
- 121. Wan Replication 3.0 datacenterA datacenter B commit WS
- 122. Wan Replication 3.0 datacenterA datacenter B WSWS WS
- 123. Wan Replication 3.0 datacenterA datacenter B WSWS WSWS Define the group segment using gmcasts.segment = 1....255
- 124. Lab 10: WANHandson! Run the application Check the traffic and the connections using iftop N P i eth1 f "port 4567" Put node3 on a second segment Run again the application What do you see when you check the traffic this time ?
- 125. Credits WSREP patches andGalera library is developed by Codership Oy Percona & Codership present tomorrow http://www.percona.com/live/london-2013/
- 126. Resources Percona XtraDB Clusterwebsite: http://www.percona.com/software/percona-xtradb-cluster/ Codership website: http://www.codership.com/wiki/doku.php PXC articles on percona's blog: http://www.percona.com/blog/category/percona-xtradb-cluster/ devops animations: http://devopsreactions.tumblr.com/
- 127. Thank you ! tutorialis OVER !
- 128. Percona provides 24 x7 Support Services Quick and Easy Access to Consultants Same Day Emergency Data Recovery Remote DBA Services sales@percona.com or 00442081330309