Merge lp:~hrvojem/percona-xtradb-cluster/bug1264394-5.6 into lp:percona-xtradb-cluster

[Hrvoje Matijakovic]

[Raghavendra D Prabhu (raghavendra-prabhu)]

review: Approve

=== modified file 'doc-pxc/source/howtos/3nodesec2.rst'
--- doc-pxc/source/howtos/3nodesec2.rst	2013-12-18 13:09:52 +0000
+++ doc-pxc/source/howtos/3nodesec2.rst	2014-01-30 13:24:56 +0000
@@ -6,7 +6,7 @@
 Assume you are running *m1.xlarge* instances with OS *Red Hat Enterprise Linux 6.1 64-bit*.
 Make sure to remove existing PXC-5.5 and PS-5.5/5.6 packages before proceeding.
 
-Install XtraDB Cluster from RPM:
+Install |Percona XtraDB Cluster| from RPM:
 
 1. Install Percona's regular and testing repositories: ::
 
@@ -32,13 +32,10 @@
         iptables -A INPUT -i eth0 -p tcp -m tcp --source 192.168.0.1/24 --dport 4567 -j ACCEPT
 
 
-5. Create /etc/my.cnf files.
+5. Create :file:`/etc/my.cnf` files.
 
  On the first node (assume IP 10.93.46.58): ::
 
-  [mysqld_safe]
-  wsrep_urls=gcomm://10.93.46.58:4567,gcomm://10.93.46.59:4567,gcomm://10.93.46.60:4567,gcomm://  
-
   [mysqld]
   datadir=/mnt/data
   user=mysql
@@ -46,6 +43,7 @@
   binlog_format=ROW
 
   wsrep_provider=/usr/lib64/libgalera_smm.so
+  wsrep_cluster_address=gcomm://10.93.46.58,10.93.46.59,10.93.46.60
 
   wsrep_slave_threads=2
   wsrep_cluster_name=trimethylxanthine
@@ -57,9 +55,6 @@
 
  On the second node (assume IP 10.93.46.59): ::
 
-  [mysqld_safe]
-  wsrep_urls=gcomm://10.93.46.58:4567,gcomm://10.93.46.59:4567,gcomm://10.93.46.60:4567,gcomm://
-
   [mysqld]
   datadir=/mnt/data
   user=mysql
@@ -67,6 +62,7 @@
   binlog_format=ROW
 
   wsrep_provider=/usr/lib64/libgalera_smm.so
+  wsrep_cluster_address=gcomm://10.93.46.58,10.93.46.59,10.93.46.60
 
   wsrep_slave_threads=2
   wsrep_cluster_name=trimethylxanthine
@@ -76,67 +72,63 @@
   innodb_locks_unsafe_for_binlog=1
   innodb_autoinc_lock_mode=2
 
-On the third (and following nodes) config is similar, with the following change: ::
+On the third (and following nodes) configuration is similar, with the following change: ::
 
   wsrep_node_name=node3
 
 In this example variable :variable:`wsrep_urls` is being used instead of :variable:`wsrep_cluster_address`. With this configuration, node will first try to reach a cluster on `10.93.46.58:4567` if there is no cluster node, then it will try on `10.93.46.59:4567` and then `10.93.46.60:4567`. If no nodes are up, it will start a new cluster. Variable :variable:`wsrep_urls` goes into the [mysql_safe] section so it's important that the mysql server instance is started with the `/bin/mysql_safe` and not `bin/mysqld`.
 
-6. Start mysqld_safe
+6. Start the |Percona XtraDB Cluster|
 
 On the first node: ::
 
-   mysqld_safe
+   [root@node1 ~]# /etc/init.d/mysql bootstrap-pxc
 
 You should be able to see in console (or in error-log file): ::
 
-  111216  0:16:42 [Note] /usr/sbin/mysqld: ready for connections.
-  Version: '5.5.17'  socket: '/var/lib/mysql/mysql.sock'  port: 3306  Percona XtraDB Cluster (GPL), Release alpha22.1, Revision 3673 wsrep_22.3.r3673
-  111216  0:16:42 [Note] WSREP: Assign initial position for certification: 0, protocol version: 1
-  111216  0:16:42 [Note] WSREP: Synchronized with group, ready for connections
+  2014-01-30 11:52:35 23280 [Note] /usr/sbin/mysqld: ready for connections.
+  Version: '5.6.15-56'  socket: '/var/lib/mysql/mysql.sock'  port: 3306  Percona XtraDB Cluster (GPL), Release 25.3, Revision 706, wsrep_25.3.r4034
+
 
 On the second (and following nodes): ::
 
-   mysqld_safe
+   [root@node2 ~]# /etc/init.d/mysql start
 
 You should be able to see in console (or in error-log file): ::
 
-  111216  0:21:39 [Note] WSREP: Flow-control interval: [12, 23]
-  111216  0:21:39 [Note] WSREP: Shifting OPEN -> PRIMARY (TO: 0)
-  111216  0:21:39 [Note] WSREP: New cluster view: global state: f912d2eb-27a2-11e1-0800-f34c520a3d4b:0, view# 2: Primary, number of nodes: 2, my index: 1, protocol version 1
-  111216  0:21:39 [Warning] WSREP: Gap in state sequence. Need state transfer.
-  111216  0:21:41 [Note] WSREP: Running: 'wsrep_sst_rsync 'joiner' '10.93.46.60' '' '/mnt/data/' '/etc/my.cnf' '1694' 2>sst.err'
-  111216  0:21:41 [Note] WSREP: Prepared SST request: rsync|10.93.46.60:4444/rsync_sst
-  111216  0:21:41 [Note] WSREP: wsrep_notify_cmd is not defined, skipping notification.
-  111216  0:21:41 [Note] WSREP: Assign initial position for certification: 0, protocol version: 1
-  111216  0:21:41 [Note] WSREP: prepared IST receiver, listening in: tcp://10.93.46.60:4568
-  111216  0:21:41 [Note] WSREP: Node 1 (node2) requested state transfer from '*any*'. Selected 0 (node1)(SYNCED) as donor.
-  111216  0:21:41 [Note] WSREP: Shifting PRIMARY -> JOINER (TO: 0)
-  111216  0:21:41 [Note] WSREP: Requesting state transfer: success, donor: 0
-  111216  0:21:42 [Note] WSREP: 0 (node1): State transfer to 1 (node2) complete.
-  111216  0:21:42 [Note] WSREP: Member 0 (node1) synced with group.
-  111216  0:21:42 [Note] WSREP: SST complete, seqno: 0
-  111216  0:21:42 [Note] Plugin 'FEDERATED' is disabled.
-  111216  0:21:42 InnoDB: The InnoDB memory heap is disabled
-  111216  0:21:42 InnoDB: Mutexes and rw_locks use GCC atomic builtins
-  111216  0:21:42 InnoDB: Compressed tables use zlib 1.2.3
-  111216  0:21:42 InnoDB: Using Linux native AIO
-  111216  0:21:42 InnoDB: Initializing buffer pool, size = 128.0M
-  111216  0:21:42 InnoDB: Completed initialization of buffer pool
-  111216  0:21:42 InnoDB: highest supported file format is Barracuda.
-  111216  0:21:42  InnoDB: Waiting for the background threads to start
-  111216  0:21:43 Percona XtraDB (http://www.percona.com) 1.1.8-20.1 started; log sequence number 1597945
-  111216  0:21:43 [Note] Event Scheduler: Loaded 0 events
-  111216  0:21:43 [Note] WSREP: Signalling provider to continue.
-  111216  0:21:43 [Note] WSREP: Received SST: f912d2eb-27a2-11e1-0800-f34c520a3d4b:0
-  111216  0:21:43 [Note] WSREP: SST finished: f912d2eb-27a2-11e1-0800-f34c520a3d4b:0
-  111216  0:21:43 [Note] /usr/sbin/mysqld: ready for connections.
-  Version: '5.5.17'  socket: '/var/lib/mysql/mysql.sock'  port: 3306  Percona XtraDB Cluster (GPL), Release alpha22.1, Revision 3673 wsrep_22.3.r3673
-  111216  0:21:43 [Note] WSREP: 1 (node2): State transfer from 0 (node1) complete.
-  111216  0:21:43 [Note] WSREP: Shifting JOINER -> JOINED (TO: 0)
-  111216  0:21:43 [Note] WSREP: Member 1 (node2) synced with group.
-  111216  0:21:43 [Note] WSREP: Shifting JOINED -> SYNCED (TO: 0)
-  111216  0:21:43 [Note] WSREP: Synchronized with group, ready for connections
+  2014-01-30 09:52:42 26104 [Note] WSREP: Flow-control interval: [28, 28]
+  2014-01-30 09:52:42 26104 [Note] WSREP: Restored state OPEN -> JOINED (2)
+  2014-01-30 09:52:42 26104 [Note] WSREP: Member 2 (percona1) synced with group.
+  2014-01-30 09:52:42 26104 [Note] WSREP: Shifting JOINED -> SYNCED (TO: 2)
+  2014-01-30 09:52:42 26104 [Note] WSREP: New cluster view: global state: 4827a206-876b-11e3-911c-3e6a77d54953:2, view# 7: Primary, number of nodes: 3, my index: 2, protocol version 2
+  2014-01-30 09:52:42 26104 [Note] WSREP: SST complete, seqno: 2
+  2014-01-30 09:52:42 26104 [Note] Plugin 'FEDERATED' is disabled.
+  2014-01-30 09:52:42 26104 [Note] InnoDB: The InnoDB memory heap is disabled
+  2014-01-30 09:52:42 26104 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
+  2014-01-30 09:52:42 26104 [Note] InnoDB: Compressed tables use zlib 1.2.3
+  2014-01-30 09:52:42 26104 [Note] InnoDB: Using Linux native AIO
+  2014-01-30 09:52:42 26104 [Note] InnoDB: Not using CPU crc32 instructions
+  2014-01-30 09:52:42 26104 [Note] InnoDB: Initializing buffer pool, size = 128.0M
+  2014-01-30 09:52:42 26104 [Note] InnoDB: Completed initialization of buffer pool
+  2014-01-30 09:52:43 26104 [Note] InnoDB: Highest supported file format is Barracuda.
+  2014-01-30 09:52:43 26104 [Note] InnoDB: 128 rollback segment(s) are active.
+  2014-01-30 09:52:43 26104 [Note] InnoDB: Waiting for purge to start
+  2014-01-30 09:52:43 26104 [Note] InnoDB:  Percona XtraDB (http://www.percona.com) 5.6.15-rel62.0 started; log sequence number 1626341
+  2014-01-30 09:52:43 26104 [Note] RSA private key file not found: /var/lib/mysql//private_key.pem. Some authentication plugins will not work.
+  2014-01-30 09:52:43 26104 [Note] RSA public key file not found: /var/lib/mysql//public_key.pem. Some authentication plugins will not work.
+  2014-01-30 09:52:43 26104 [Note] Server hostname (bind-address): '*'; port: 3306
+  2014-01-30 09:52:43 26104 [Note] IPv6 is available.
+  2014-01-30 09:52:43 26104 [Note]   - '::' resolves to '::';
+  2014-01-30 09:52:43 26104 [Note] Server socket created on IP: '::'.
+  2014-01-30 09:52:43 26104 [Note] Event Scheduler: Loaded 0 events
+  2014-01-30 09:52:43 26104 [Note] /usr/sbin/mysqld: ready for connections.
+  Version: '5.6.15-56'  socket: '/var/lib/mysql/mysql.sock'  port: 3306  Percona XtraDB Cluster (GPL), Release 25.3, Revision 706, wsrep_25.3.r4034
+  2014-01-30 09:52:43 26104 [Note] WSREP: inited wsrep sidno 1
+  2014-01-30 09:52:43 26104 [Note] WSREP: wsrep_notify_cmd is not defined, skipping notification.
+  2014-01-30 09:52:43 26104 [Note] WSREP: REPL Protocols: 5 (3, 1)
+  2014-01-30 09:52:43 26104 [Note] WSREP: Assign initial position for certification: 2, protocol version: 3
+  2014-01-30 09:52:43 26104 [Note] WSREP: Service thread queue flushed.
+  2014-01-30 09:52:43 26104 [Note] WSREP: Synchronized with group, ready for connections
 
 When all nodes are in SYNCED stage your cluster is ready!
 

=== modified file 'doc-pxc/source/howtos/singlebox.rst'
--- doc-pxc/source/howtos/singlebox.rst	2013-09-05 13:37:01 +0000
+++ doc-pxc/source/howtos/singlebox.rst	2014-01-30 13:24:56 +0000
@@ -1,7 +1,10 @@
+.. _singe_box:
+
+==========================================
 How to setup 3 node cluster on single box
 ==========================================
 
-This example shows how to setup 3-node cluster on the single physical box. Assume you installed |Percona XtraDB Cluster| from binary .tar.gz into directory :: 
+This example shows how to setup 3-node cluster on the single physical box. Assume you installed |Percona XtraDB Cluster| from binary ``.tar.gz`` into directory :: 
 
 /usr/local/Percona-XtraDB-Cluster-5.5.24-23.6.342.Linux.x86_64
 
@@ -21,9 +24,9 @@
 
 In this example local IP address is 192.168.2.21
 
-Then we should be able to start initial node as (from directory /usr/local/Percona-XtraDB-Cluster-5.5.24-23.6.342.Linux.x86_64): ::
+Then we should be able to start initial node as (from directory :file:`/usr/local/Percona-XtraDB-Cluster-5.6.15-25.3.706.Linux.x86_64`): ::
 
-        bin/mysqld_safe --defaults-file=/etc/my.4000.cnf
+        bin/mysqld_safe --defaults-file=/etc/my.4000.cnf --wsrep-new-cluster
 
 Following output will let out know that node was started successfully: ::
 
@@ -61,24 +64,20 @@
         
         mysql -h127.0.0.1 -P5000 -e "CREATE DATABASE hello_peter"
 
-In this example variable :variable:`wsrep_urls` is being used instead of :variable:`wsrep_cluster_address`. With this configuration, node will first try to reach a cluster on port 4030, if there is no cluster node, then it will try on port 5030 and then 6030. If no nodes are up, it will start a new cluster. Variable :variable:`wsrep_urls` goes into the [mysql_safe] section so it's important that the mysql server instance is started with the `/bin/mysql_safe` and not `bin/mysqld`.
-
 Configuration files (/etc/my.4000.cnf): ::
 
   /etc/my.4000.cnf
 
-  [mysqld_safe]
-  wsrep_urls=gcomm://192.168.2.21:4030,gcomm://192.168.2.21:5030,gcomm://192.168.2.21:6030,gcomm://
-
   [mysqld]
   port = 4000
   socket=/tmp/mysql.4000.sock
   datadir=/data/bench/d1
-  basedir=/usr/local/Percona-XtraDB-Cluster-5.5.24-23.6.342.Linux.x86_64
+  basedir=/usr/local/Percona-XtraDB-Cluster-5.6.15-25.3.706.Linux.x86_64
   user=mysql
   log_error=error.log
   binlog_format=ROW
-  wsrep_provider=/usr/local/Percona-XtraDB-Cluster-5.5.24-23.6.342.Linux.x86_64/lib/libgalera_smm.so
+  wsrep_cluster_address='gcomm://192.168.2.21:5030,192.168.2.21:6030'
+  wsrep_provider=/usr/local/Percona-XtraDB-Cluster-5.6.15-25.3.706.Linux.x86_64/lib/libgalera_smm.so
   wsrep_sst_receive_address=192.168.2.21:4020
   wsrep_node_incoming_address=192.168.2.21 
   wsrep_slave_threads=2
@@ -94,18 +93,16 @@
 
   /etc/my.5000.cnf
 
-  [mysqld_safe]
-  wsrep_urls=gcomm://192.168.2.21:4030,gcomm://192.168.2.21:5030,gcomm://192.168.2.21:6030,gcomm://
-
   [mysqld]
   port = 5000
   socket=/tmp/mysql.5000.sock
   datadir=/data/bench/d2
-  basedir=/usr/local/Percona-XtraDB-Cluster-5.5.24-23.6.342.Linux.x86_64
+  basedir=/usr/local/Percona-XtraDB-Cluster-5.6.15-25.3.706.Linux.x86_64
   user=mysql
   log_error=error.log
   binlog_format=ROW
-  wsrep_provider=/usr/local/Percona-XtraDB-Cluster-5.5.24-23.6.342.Linux.x86_64/lib/libgalera_smm.so
+  wsrep_cluster_address='gcomm://192.168.2.21:4030,192.168.2.21:6030'
+  wsrep_provider=/usr/local/Percona-XtraDB-Cluster-5.6.15-25.3.706.Linux.x86_64/lib/libgalera_smm.so
   wsrep_sst_receive_address=192.168.2.21:5020
   wsrep_node_incoming_address=192.168.2.21 
   wsrep_slave_threads=2
@@ -120,18 +117,16 @@
 
   /etc/my.6000.cnf
 
-  [mysqld_safe]
-  wsrep_urls=gcomm://192.168.2.21:4030,gcomm://192.168.2.21:5030,gcomm://192.168.2.21:6030,gcomm://
-
   [mysqld]
   port = 6000
   socket=/tmp/mysql.6000.sock
   datadir=/data/bench/d3
-  basedir=/usr/local/Percona-XtraDB-Cluster-5.5.24-23.6.342.Linux.x86_64
+  basedir=/usr/local/Percona-XtraDB-Cluster-5.6.15-25.3.706.Linux.x86_64
   user=mysql
   log_error=error.log
   binlog_format=ROW
-  wsrep_provider=/usr/local/Percona-XtraDB-Cluster-5.5.24-23.6.342.Linux.x86_64/lib/libgalera_smm.so
+  wsrep_cluster_address='gcomm://192.168.2.21:4030,192.168.2.21:5030'
+  wsrep_provider=/usr/local/Percona-XtraDB-Cluster-5.6.15-25.3.706.Linux.x86_64/lib/libgalera_smm.so
   wsrep_sst_receive_address=192.168.2.21:6020
   wsrep_node_incoming_address=192.168.2.21 
   wsrep_slave_threads=2

=== modified file 'doc-pxc/source/index.rst'
--- doc-pxc/source/index.rst	2014-01-29 15:10:12 +0000
+++ doc-pxc/source/index.rst	2014-01-30 13:24:56 +0000
@@ -7,10 +7,6 @@
  Percona XtraDB Cluster 5.6 Documentation
 ==========================================
 
-.. note::
-
-   Please note: |Percona XtraDB Cluster| 5.6 is RELEASE CANDIDATE quality software. It should *NOT* be used in production environments. Refer to :ref:`upgrading_guide` for upgrade guide.
-
 |Percona XtraDB Cluster| is High Availability and Scalability solution for MySQL Users.
 
 |Percona XtraDB Cluster| provides:

=== modified file 'doc-pxc/source/release-notes/Percona-XtraDB-Cluster-5.6.15-25.3.rst'
--- doc-pxc/source/release-notes/Percona-XtraDB-Cluster-5.6.15-25.3.rst	2014-01-29 15:47:41 +0000
+++ doc-pxc/source/release-notes/Percona-XtraDB-Cluster-5.6.15-25.3.rst	2014-01-30 13:24:56 +0000
@@ -22,7 +22,9 @@
 
  Node would get stuck and required restart if ``DDL`` was performed after ``FLUSH TABLES WITH READ LOCK``. Bug fixed :bug:`1265656`.
 
- Default value for :variable:`binlog_format` is now ``ROW`` and for :variable:`innodb_autoinc_lock_mode` is ``2``. This is done so that |Percona XtraDB Cluster| is not started with wrong defaults leading to non-deterministic outcomes like crash. Bug fixed :bug:`1243228`.
+ Galera provider pause has been fixed to avoid potential deadlock with replicating threads.
+
+ Default value for :variable:`binlog_format` is now ``ROW``. This is done so that |Percona XtraDB Cluster| is not started with wrong defaults leading to non-deterministic outcomes like crash. Bug fixed :bug:`1243228`.
 
  During the installation of ``percona-xtradb-cluster-garbd-3.x`` package, *Debian* tries to start it, but as the configuration is not set, it would fail to start and leave the installation in ``iF`` state. Bug fixed :bug:`1262171`.
 
@@ -39,8 +41,16 @@
  Binary log directory is now being cleanup as part of the :ref:`XtraBackup SST <xtrabackup_sst>`. Bug fixed :bug:`1273368`.
 
  First connection would hang after changing the :variable:`wsrep_cluster_address` variable. Bug fixed :bug:`1022250`.
-
- Fixed multiple build bugs: :bug:`1262716`, :bug:`1269063`, :bug:`1269351`, :bug:`1272723`,  :bug:`1272732`.
+ 
+ When :variable:`gmcast.listen_addr` was set manually it did not allow nodes own address in gcomm address list. Bug fixed :bug:`1099478`.
+
+ GCache file allocation could fail if file size was a multiple of page size. Bug fixed :bug:`1259952`.
+
+ Group remerge after partitioning event has been fixed. Bug fixed :bug:`1232747`.
+
+ Fixed the OpenSSL linking exceptions. Bug fixed :bug:`1259063`.
+
+ Fixed multiple build bugs: :bug:`1262716`, :bug:`1269063`, :bug:`1269351`, :bug:`1272723`, :bug:`1272732`, and :bug:`1261996`.
 
 Other bugs fixed: :bug:`1273101`, :bug:`1272961`, :bug:`1271264`, and :bug:`1253055`.
 

=== modified file 'doc-pxc/source/upgrading_guide_55_56.rst'
--- doc-pxc/source/upgrading_guide_55_56.rst	2014-01-29 23:50:44 +0000
+++ doc-pxc/source/upgrading_guide_55_56.rst	2014-01-30 13:24:56 +0000
@@ -56,7 +56,7 @@
     # Required under certain conditions
     read_only=ON
 
-**Step #5.1** "read_only=ON" is required only when the tables you have contain timestamp/datetime/time data types as those data types are incompatible across replication from higher version to lower. This is currently a limitation of mysql itself. Also, refer to `Replication compatibility guide https://dev.mysql.com/doc/refman/5.6/en/replication-compatibility.html>`_. Any DDLs during migration are not recommended for the same reason.
+**Step #5.1** "read_only=ON" is required only when the tables you have contain timestamp/datetime/time data types as those data types are incompatible across replication from higher version to lower. This is currently a limitation of mysql itself. Also, refer to `Replication compatibility guide <https://dev.mysql.com/doc/refman/5.6/en/replication-compatibility.html>`_. Any DDLs during migration are not recommended for the same reason.
 
 **Step #5.2** To ensure 5.6 read-only nodes are not written to during migration, clustercheck (usually used with xinetd and HAProxy) distributed with PXC has been modified to return 503 when the node is read-only so that HAProxy doesn't send writes to it. Refer to clustercheck script for more details. Instead, you can also opt for read-write splitting at load-balancer/proxy level or at application level.
 
@@ -134,16 +134,33 @@
 
 **Step #3** Fix the variables in the |MySQL| configuration file :file:`my.cnf` which are not compatible with |Percona Server| 5.6. Detailed list can be checked in `Changed in Percona Server 5.6 <http://www.percona.com/doc/percona-server/5.6/changed_in_56.html>`_ documentation. Add the following to :file:`my.cnf` for compatibility with 5.5 replication for the duration of upgrade, add 'socket.checksum=1' to the :variable:`wsrep_provider_options` variable and set :variable:`wsrep_provider` set to ``none`` ::
 
+    # Required for compatibility with galera-2
+    # Append socket.checksum=1 to other options if others are in wsrep_provider_options. Eg.: "gmcast.listen_addr=tcp://127.0.0.1:15010; socket.checksum=1"
     wsrep_provider_options="socket.checksum=1"
-    wsrep_provider=none
+    # Required for replication compatibility
     log_bin_use_v1_row_events=1
     gtid_mode=0
     binlog_checksum=NONE
-    wsrep-slave-threads=1
+    # Required under certain conditions
+    read_only=ON
+
+**Step #3.1** "read_only=ON" is required only when the tables you have contain timestamp/datetime/time data types as those data types are incompatible across 
+replication from higher version to lower. This is currently a limitation of mysql itself. Also, refer to `Replication compatibility guide <https://dev.mysql.c
+om/doc/refman/5.6/en/replication-compatibility.html>`_. Any DDLs during migration are not recommended for the same reason.
+
+**Step #3.2** To ensure 5.6 read-only nodes are not written to during migration, clustercheck (usually used with xinetd and HAProxy) distributed with PXC has 
+been modified to return 503 when the node is read-only so that HAProxy doesn't send writes to it. Refer to clustercheck script for more details. Instead, you 
+can also opt for read-write splitting at load-balancer/proxy level or at application level.
+
+.. note::
+    On the last 5.5 node to upgrade to 5.6, the compatibility options of Step #3 are not required since all other nodes will already be upgrade and their configuration options are compatible with a 5.6 node without them.
 
 **Step #4** Install the new packages: ::
 
-    # apt-get install percona-xtradb-cluster-server-5.6 percona-xtradb-cluster-client-5.6 percona-xtrabackup percona-xtradb-cluster-galera-3.x
+    # apt-get install percona-xtradb-cluster-56
+
+.. note::
+    For more details on installation, refer to :ref:`installation` guide. You may also want to install percona-xtradb-cluster-full-56 which installs other ancillary packages like '-shared-56', '-test-56', debuginfos and so on.
 
 **Step #5** After node has been started you'll need to run ``mysql_upgrade``: ::
 
@@ -163,9 +180,31 @@
 
 **Step #9**   After this has been set up all 5.5 nodes can be upgraded, one-by-one, as described in the Stage I. 
 
-  a) After all nodes in the cluster are upgraded to 5.6, option :variable:`read_only` should be set to ``OFF``. 
-
-  b) Nodes should be restarted with compatibility options added earlier removed/updated for optimal performance (though cluster will continue run with those options).
-
-
- 
+  a) If :variable:`read_only` was turned on in Step #3.1, then after all nodes in the cluster are upgraded to 5.6 or equivalently, after the last 5.5 has been take down for upgrade, option :variable:`read_only` can be set to ``OFF`` (since this is a dynamic variable, it can done without restart).
+
+  b) If read-write splitting was done in applications and/or in load-balancer then in previous step, instead of ``read_only``, writes need to be directed to 5.6 nodes.
+
+Stage III [Optional]
+--------------------
+
+**Step #10** This step is required to turn off the options added in #Step 3. Note, that this step is not required immediately after upgrade and can be done at a latter stage. The aim here is to turn off the compatibility options for performance reasons (only socket.checksum=1 fits this). This requires restart of each node. Hence, following can be removed/commented-out::
+
+    # Remove socket.checksum=1 from other options if others are in wsrep_provider_options. Eg.: "gmcast.listen_addr=tcp://127.0.0.1:15010"
+    # Removing this makes socket.checksum=2 which uses hardware accelerated CRC32 checksumming.
+    wsrep_provider_options="socket.checksum=1"
+
+    # Required for replication compatibility, being removed here.
+    # You can keep some of these if you wish.
+    log_bin_use_v1_row_events=1
+
+    # You will need this if you need to add async-slaves
+    gtid_mode=0
+
+    # Galera already has full writeset checksumming, so 
+    # this is required only if async-slaves are there or 
+    # binlogging is turned on.
+    binlog_checksum=NONE
+
+    # Remove it from cnf even though it was turned off at runtime in Step #11.
+    read_only=ON
+