I have 3 master servers, different DBs, I am trying to replicate into a single server. I am having a hard time getting them setup and current. I have Duplicate Entry errors on all 3 Channels. Skipping them manually is painful to say the least. Is there a way to auto sync to the correct position? I was under the impression that this was easy as pie with GTID.
I used:
Dump:
mysqldump --databases profiles --single-transaction --triggers --routines --host=10.10.10.10 --port=3306 --user=user --password=pass > ~/dump.sql
Initialize:
CHANGE MASTER TO MASTER_HOST="10.10.10.10", MASTER_PORT=3306, MASTER_USER="user", MASTER_PASSWORD="pass", MASTER_AUTO_POSITION=1 FOR CHANNEL "channel1";
Master My.cnf:
gtid_mode = ON
enforce_gtid_consistency = true
log_bin = /var/log/mysql/bin_log.index
log_slave_updates = true
server-id = 2061
Slave My.cnf:
[client]
port = 3306
socket = /var/run/mysqld/mysqld.sock
[mysqld_safe]
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
nice = 0
[mysqld]
user = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /var/lib/mysql
tmpdir = /tmp
lc-messages-dir = /usr/share/mysql
server-id = 10001
explicit_defaults_for_timestamp
gtid_mode=ON
enforce_gtid_consistency=true
log_bin=/var/log/mysql/bin_log.index
log_slave_updates=true
master_info_repository=TABLE
relay_log_info_repository=TABLE
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
#bind-address = 127.0.0.1
log-error = /var/log/mysql/error.log
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
Am I missing something? Any help is appreciated.
The problem was that GLOBAL.GTID_PURGED had only registered one of my master databases, which sets the proper position from which to continue the replication process.
The other databases were starting from the beginning of time essentially.
Thus the improper positioning and the Duplicate record errors I was receiving.
So this was my solution:
MySQL Multi-Source GTID Replication Guide by ME:
Re/Install MySQL Server:
After securing the current data I performed a clean install of MySQL Server 5.7.7-rc onto the slave server. Any MySQL Server can be completely removed using the following:
$ sudo apt-get --purge remove mysql-client mysql-server mysql-common
$ sudo apt-get autoremove
and then selecting YES at the prompt to remove the "Data" directory (This will permanently delete all of your databases, configurations, etc.). If you have any custom configurations, now is the time to backup your /etc/mysql/my.cnf file.
Reinstall MySQL Server 5.7 for Ubuntu 14-lts
$ sudo apt-get install mysql-server-5.7
If you don't have 5.7 on your system use this guide
Backup Live Master Databases:
I created a current MySQL Dump of all 3 Live Master databases. Each of my databases have a different name e.g. db01, db02, db03 and they are being saved directly onto the slave server.
In my case each database is on its own server, so I ran this a few times changing the ip and database, and filename.
$ mysqldump -u username -p -h 10.10.10.10 --skip-lock-tables --single-transaction --triggers --routines --databases db01 > ~/dumpDB01.sql
Once complete, you will need the GTID_PURGED data from each dump and save it for later:
$ grep PURGED ~/dumpDB01.sql
SET ##GLOBAL.GTID_PURGED='d23dceda-08a4-11e5-85e4-005056a2431f:1-10073';
You will need this entire string: d23dceda-08a4-11e5-85e4-005056a2431f:1-10073
MySQL Slave Server Configuration:
Now I decided to completely configure mysql before I ever imported any data and I will explain why shortly.
Edit my.cnf:
sudo vi /etc/mysql/my.cnf
gtid_mode =ON
enforce_gtid_consistency =true
log_bin =/var/log/mysql/bin_log.index
log_slave_updates =true
master_info_repository =TABLE
relay_log_info_repository =TABLE
server-id =1001
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
#bind-address = 127.0.0.1
You will need to save the configuration file and create the bin_log.index file, otherwise the server will not start.
$ sudo touch /var/log/mysql/bin_log.index
$ sudo chown mysql:mysql /var/log/mysql/bin_log.index
$ sudo service mysql restart
Import / Configure Data:
While importing the dumps, the first one will register its GTID_PURGED automatically like this:
SET ##GLOBAL.GTID_PURGED='d23dceda-08a4-11e5-85e4-005056a2431f:1-10073';
Once this happens your GTID_EXECUTED will be set with the same data, and each subsequent import will produce errors like this:
ERROR 1840 (HY000) at line 24: ##GLOBAL.GTID_PURGED can only be set when ##GLOBAL.GTID_EXECUTED is empty.
These errors can be ignored on import with $ mysql -u username -p -f < ~/dumpDB02.sql as we are going to modify the GTID_PURGED manually after the import process. If you have already forced the imports and have seen this error you can clear both GTID variables by executing mysql > RESET MASTER;
From the mysql console run the following:
mysql> RESET MASTER;
You will need all 3 GTIDs from the dumps and comma separate them in the assignment below.
mysql> SET ##GLOBAL.GTID_PURGED='d23dceda-08a4-11e5-85e4-005056a2431f:1-10073,d23dceda-08a4-11e5-85e4-005056a2431f:1-10073,d23dceda-08a4-11e5-85e4-005056a2431f:1-10073';
You can now initialize and start replication:
For each database (in my case I changed the ip and channel is a string of your choice. You will use this channel to access the slave data):
mysql> CHANGE MASTER TO MASTER_HOST="10.10.10.10", MASTER_PORT=3306, MASTER_USER="username", MASTER_PASSWORD="password", MASTER_AUTO_POSITION=1 FOR CHANNEL "db01";
Then start each slave:
mysql> START SLAVE FOR CHANNEL "db01";
mysql> SHOW SLAVE STATUS FOR CHANNEL "db01"\G
and success!
I have all of the data, no errors, and its now up to date with the Master Servers
I currently have one master server and want to add another master server for fail over.
On the primary server I've added the following to "my.ini"
server-id = 1
replicate-same-server-id = 0
auto-increment-increment = 2
auto-increment-offset = 1
log_bin=mysql-bin
log_error=mysql-bin.err
binlog_do_db=1
binlog_do_db=2
binlog_do_db=3
binlog_do_db=4
Once adding:
master-host = [IP]
master-user = [usernameslaveuser]
master-password = [password]
master-connect-retry = 30
The mysql server no longer starts up...
So I decided to first get the secondary server to work properly.
Problem 2:
On the new server I've copied over my user files from the "data"/mysql dir of the primary.
I've also imported all databases with MySQL work bench.
Then I added this to "my.ini":
server-id=2
replicate-same-server-id = 0
auto-increment-increment = 2
auto-increment-offset = 2
master-host = [IP]
master-user = [usernameslaveuser]
master-password = [password]
master-connect-retry = 30
log_bin=mysql-bin
log_error=mysql-bin.err
binlog_do_db=1
binlog_do_db=2
binlog_do_db=3
binlog_do_db=4
The server starts up fine, so I decided to add a table inside a replicating database on the master but the changes where not copied over to the secondary server...
I googled a bit and found that I have to run some commands in the mysql command line to make replication work.
But when I open this on the secondary server it doesn't start...
When opening it in the command prompt it says mysql.exe: unknown variable 'server-id=2"
Both servers are running Windows Server 2012 R2 and have MySQL 5.6.15 64bit installed.
Can someone guide me true the last part of setting this up?
Specifying as below in my.cnf(linux) or my.ini(windows) file is no longer supported in latest versions of MySQL
master-host = [IP]
master-user = [usernameslaveuser]
master-password = [password]
master-connect-retry = 30
You should execute this query instead:
CHANGE MASTER TO MASTER_HOST='host name/ip',MASTER_USER='user',MASTER_PASSWORD='pwd', MASTER_PORT=3306, MASTER_CONNECT_RETRY=30;
I've resolved problem 2: I wasn't putting it in the mysqld part but in the mysql part of the my.ini
Resolved problem 1: had to run it in the MySQL command line.
I am trying to replicate my database using master slave replication on my wamp server. I have made the following changes to my my.ini file:
# Number of threads allowed inside the InnoDB kernel.The optimal value
# depends highly on the application, hardware as well as the OS
# scheduler properties. A too high value may lead to thread thrashing.
innodb_thread_concurrency=8
#Defining the directory for logs and database and the server id
log-bin=C:\wamp\logs\mysql-bin.log
binlog-do-db=bank
server-id=2
On Master Server I configured this:
mysql> GRANT REPLICATION SLAVE
-> ON *.* TO 'root'#'slave_ip'
-> IDENTIFIED BY '';
On the slave server, I configured this:
mysql> CHANGE MASTER TO
-> MASTER_HOST='(master_ip)',
-> MASTER_PORT=3306,
-> MASTER_USER='root',
-> MASTER_PASSWORD='';
I got the error: Error 1198: This operation cannot be performed with a running slave; run stop slave first.
So I ran stop slave and nothing happened. Any help would be appreciated.
on master:
SHOW MASTER STATUS;
output is :
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000001 | 107 | karbord_test | |
+------------------+----------+--------------+------------------+
1 row in set
on slave:
STOP SLAVE;
CHANGE MASTER TO
MASTER_LOG_FILE='mysql-bin.000001',
MASTER_LOG_POS=107;
START SLAVE;
I have a web app with 2 web servers and 2 database servers. The dbs are setup for multi master replication. (this is the primary environment)
I also have the exact same setup on a different location acting as standby, in case the primary env fails. (this is the backup env)
What I need is for the backup env to be in sync with the dbs of the primary site. However, all dbs in both environments have already replication configured.
How can I achieve my goal?
Thanks
If this is standard MySQL rather than MySQL Cluster (and from your setup I think is has to be), you can't AFAIK.
If you have hierarchical replication then you could make it work, but with multimaster you can't. The basic problem is that a slave can only have one master which is set by the CHANGE MASTER TO command.
MySQL Cluster operates in a more complex manner, you have several servers in each cluster and then the cluster can be replicated to another cluster... or something.
Not very helpful I'm afraid.
You can sync the backup servers to one of the other masters, but the backup servers would not be masters to each other until you have a problem and then you change the master slave relationships yourself.
1 Configure The Master
First we have to edit /etc/mysql/my.cnf. or /etc/my.cnf We have to enable networking for MySQL, and MySQL should listen on all IP addresses, therefore we comment out these lines (if existant):
#skip-networking
skip-external-locking
bind-address=0.0.0.0
log-bin=mysql-bin.log
binlog-do-db=exampledb (database name)
server-id=1
Then we restart MySQL:
/etc/init.d/mysql restart
Create a user with replication privileges
GRANT REPLICATION SLAVE ON *.* TO 'slave_user'#'%' IDENTIFIED BY '<some_password>'; (Replace <some_password> with a real password!)Â
FLUSH PRIVILEGES;
Take dump of database(exampledb) and run command
SHOW MASTER STATUS
It will give you result like
---------------+----------+--------------+------------------+
| File | Position | Binlog_do_db | Binlog_ignore_db |
+---------------+----------+--------------+------------------+
| mysql-bin.006 | 183 | database name| |
+---------------+----------+--------------+------------------+
1 row in set (0.00 sec
Write down this information, we will need it later on the slave!
Then leave the MySQL shell:
quit;
2 Configure The Slave
On the slave we first have to create the sample database exampledb:
mysql -u root -p
Enter password:
CREATE DATABASE exampledb;
quit;
store databse dump on slave
Now we have to tell MySQL on the slave that it is the slave, that the master is 192.168.0.100, and that the master database to watch is exampledb. Therefore we add the following lines to /etc/mysql/my.cnf or /etc/my.cnf if file doesnot exists copy from other location
server-id=2
master-host=192.168.0.100(ip address of master host machine)
master-user=slave_user(user name)
master-password=secret (password)
master-connect-retry=60
replicate-do-db=exampledb (database name)
Then we restart MySQL:
/etc/init.d/mysql restart
Finally, we must do this:
mysql -u root -p
Enter password:
SLAVE STOP;
In the next command (still on the MySQL shell) you have to replace the values appropriately:
CHANGE MASTER TO MASTER_HOST=’master ip address’, MASTER_USER='slave_user', MASTER_PASSWORD='<some_password>', MASTER_LOG_FILE='mysql-bin.006', MASTER_LOG_POS=183;
MASTER_HOST is the IP address or hostname of the master (in this example it is 192.168.0.100).
MASTER_USERÂ is the user we granted replication privileges on the master.
MASTER_PASSWORD is the password of MASTER_USER on the master.
MASTER_LOG_FILE is the file MySQL gave back when you ran SHOW MASTER STATUS; on the master.
MASTER_LOG_POS is the position MySQL gave back when you ran SHOW MASTER STATUS; on the master.
Now all that is left to do is start the slave. Still on the MySQL shell we run
START SLAVE;
quit;
That's it! Now whenever exampledb is updated on the master, all changes will be replicated to exampledb on the slave. Test it!
Mysql Server1 is running as MASTER.
Mysql Server2 is running as SLAVE.
Now DB replication is happening from MASTER to SLAVE.
Server2 is removed from network and re-connect it back after 1 day. After this there is mismatch in database in master and slave.
How to re-sync the DB again as after restoring DB taken from Master to Slave also doesn't solve the problem ?
This is the full step-by-step procedure to resync a master-slave replication from scratch:
At the master:
RESET MASTER;
FLUSH TABLES WITH READ LOCK;
SHOW MASTER STATUS;
And copy the values of the result of the last command somewhere.
Without closing the connection to the client (because it would release the read lock) issue the command to get a dump of the master:
mysqldump -u root -p --all-databases > /a/path/mysqldump.sql
Now you can release the lock, even if the dump hasn't ended yet. To do it, perform the following command in the MySQL client:
UNLOCK TABLES;
Now copy the dump file to the slave using scp or your preferred tool.
At the slave:
Open a connection to mysql and type:
STOP SLAVE;
Load master's data dump with this console command:
mysql -uroot -p < mysqldump.sql
Sync slave and master logs:
RESET SLAVE;
CHANGE MASTER TO MASTER_LOG_FILE='mysql-bin.000001', MASTER_LOG_POS=98;
Where the values of the above fields are the ones you copied before.
Finally, type:
START SLAVE;
To check that everything is working again, after typing:
SHOW SLAVE STATUS;
you should see:
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
That's it!
The documentation for this at the MySQL site is woefully out of date and riddled with foot-guns (such as interactive_timeout). Issuing FLUSH TABLES WITH READ LOCK as part of your export of the master generally only makes sense when coordinated with a storage/filesystem snapshot such as LVM or zfs.
If you are going to use mysqldump, you should rely instead on the --master-data option to guard against human error and release the locks on the master as quickly as possible.
Assume the master is 192.168.100.50 and the slave is 192.168.100.51, each server has a distinct server-id configured, the master has binary logging on and the slave has read-only=1 in my.cnf
To stage the slave to be able to start replication just after importing the dump, issue a CHANGE MASTER command but omit the log file name and position:
slaveserver> CHANGE MASTER TO MASTER_HOST='192.168.100.50', MASTER_USER='replica', MASTER_PASSWORD='asdmk3qwdq1';
Issue the GRANT on the master for the slave to use:
masterserver> GRANT REPLICATION SLAVE ON *.* TO 'replica'#'192.168.100.51' IDENTIFIED BY 'asdmk3qwdq1';
Export the master (in screen) using compression and automatically capturing the correct binary log coordinates:
mysqldump --master-data --all-databases --flush-privileges | gzip -1 > replication.sql.gz
Copy the replication.sql.gz file to the slave and then import it with zcat to the instance of MySQL running on the slave:
zcat replication.sql.gz | mysql
Start replication by issuing the command to the slave:
slaveserver> START SLAVE;
Optionally update the /root/.my.cnf on the slave to store the same root password as the master.
If you are on 5.1+, it is best to first set the master's binlog_format to MIXED or ROW. Beware that row logged events are slow for tables which lack a primary key. This is usually better than the alternative (and default) configuration of binlog_format=statement (on master), since it is less likely to produce the wrong data on the slave.
If you must (but probably shouldn't) filter replication, do so with slave options replicate-wild-do-table=dbname.% or replicate-wild-ignore-table=badDB.% and use only binlog_format=row
This process will hold a global lock on the master for the duration of the mysqldump command but will not otherwise impact the master.
If you are tempted to use mysqldump --master-data --all-databases --single-transaction (because you only using InnoDB tables), you are perhaps better served using MySQL Enterprise Backup or the open source implementation called xtrabackup (courtesy of Percona)
Unless you are writing directly to the slave (Server2) the only problem should be that Server2 is missing any updates that have happened since it was disconnected. Simply restarting the slave with "START SLAVE;" should get everything back up to speed.
I am very late to this question, however I did encounter this problem and, after much searching, I found this information from Bryan Kennedy: http://plusbryan.com/mysql-replication-without-downtime
On Master take a backup like this:
mysqldump --skip-lock-tables --single-transaction --flush-logs --hex-blob --master-data=2 -A > ~/dump.sql
Now, examine the head of the file and jot down the values for MASTER_LOG_FILE and MASTER_LOG_POS. You will need them later:
head dump.sql -n80 | grep "MASTER_LOG"
Copy the "dump.sql" file over to Slave and restore it:
mysql -u mysql-user -p < ~/dump.sql
Connect to Slave mysql and run a command like this:
CHANGE MASTER TO MASTER_HOST='master-server-ip', MASTER_USER='replication-user', MASTER_PASSWORD='slave-server-password', MASTER_LOG_FILE='value from above', MASTER_LOG_POS=value from above; START SLAVE;
To check the progress of Slave:
SHOW SLAVE STATUS;
If all is well, Last_Error will be blank, and Slave_IO_State will report “Waiting for master to send event”.
Look for Seconds_Behind_Master which indicates how far behind it is.
YMMV. :)
I think, Maatkit utilits helps for you! You can use mk-table-sync. Please see this link: http://www.maatkit.org/doc/mk-table-sync.html
Here is what I typically do when a mysql slave gets out of sync. I have looked at mk-table-sync but thought the Risks section was scary looking.
On Master:
SHOW MASTER STATUS
The outputted columns (File, Position) will be of use to us in a bit.
On Slave:
STOP SLAVE
Then dump the master db and import it to the slave db.
Then run the following:
CHANGE MASTER TO
MASTER_LOG_FILE='[File]',
MASTER_LOG_POS=[Position];
START SLAVE;
Where [File] and [Position] are the values outputted from the "SHOW MASTER STATUS" ran above.
Hope this helps!
Following up on David's answer...
Using SHOW SLAVE STATUS\G will give human-readable output.
Master:
mysqldump -u root -p --all-databases --master-data | gzip > /tmp/dump.sql.gz
scp master:/tmp/dump.sql.gz slave:/tmp/ Move dump file to slave server
Slave:
STOP SLAVE;
zcat /tmp/dump.sql.gz | mysql -u root -p
START SLAVE;
SHOW SLAVE STATUS;
NOTE:
On master you can run SET GLOBAL expire_logs_days = 3 to keep binlogs for 3 days in case of slave issues.
Here is a complete answer that will hopefully help others...
I want to setup mysql replication using master and slave, and since the only thing I knew was that it uses log file(s) to synchronize, if the slave goes offline and gets out of sync, in theory it should only need to connect back to its master and keep reading the log file from where it left off, as user malonso mentioned.
So here are the test result after configuring the master and slave as mentioned by: http://dev.mysql.com/doc/refman/5.0/en/replication-howto.html ...
Provided you use the recommended master/slave configuration and don't write to the slave, he and I where right (as far as mysql-server 5.x is concerned). I didn't even need to use "START SLAVE;", it just caught up to its master. But there is a default 88000 something retries every 60 second so I guess if you exhaust that you might have to start or restart the slave. Anyways, for those like me who wanted to know if having a slave going offline and back up again requires manual intervention.. no, it doesn't.
Maybe the original poster had corruption in the log-file(s)? But most probably not just a server going off-line for a day.
pulled from /usr/share/doc/mysql-server-5.1/README.Debian.gz which probably makes sense to non debian servers as well:
* FURTHER NOTES ON REPLICATION
===============================
If the MySQL server is acting as a replication slave, you should not
set --tmpdir to point to a directory on a memory-based filesystem or to
a directory that is cleared when the server host restarts. A replication
slave needs some of its temporary files to survive a machine restart so
that it can replicate temporary tables or LOAD DATA INFILE operations. If
files in the temporary file directory are lost when the server restarts,
replication fails.
you can use something sql like: show variables like 'tmpdir'; to find out.
Adding to the popular answer to include this error:
"ERROR 1200 (HY000): The server is not configured as slave; fix in config file or with CHANGE MASTER TO",
Replication from slave in one shot:
In one terminal window:
mysql -h <Master_IP_Address> -uroot -p
After connecting,
RESET MASTER;
FLUSH TABLES WITH READ LOCK;
SHOW MASTER STATUS;
The status appears as below: Note that position number varies!
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000001 | 98 | your_DB | |
+------------------+----------+--------------+------------------+
Export the dump similar to how he described "using another terminal"!
Exit and connect to your own DB(which is the slave):
mysql -u root -p
The type the below commands:
STOP SLAVE;
Import the Dump as mentioned (in another terminal, of course!) and type the below commands:
RESET SLAVE;
CHANGE MASTER TO
MASTER_HOST = 'Master_IP_Address',
MASTER_USER = 'your_Master_user', // usually the "root" user
MASTER_PASSWORD = 'Your_MasterDB_Password',
MASTER_PORT = 3306,
MASTER_LOG_FILE = 'mysql-bin.000001',
MASTER_LOG_POS = 98; // In this case
Once logged, set the server_id parameter (usually, for new / non-replicated DBs, this is not set by default),
set global server_id=4000;
Now, start the slave.
START SLAVE;
SHOW SLAVE STATUS\G;
The output should be the same as he described.
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Note: Once replicated, the master and slave share the same password!
Rebuilding the slave using LVM
Here is the method we use to rebuild MySQL slaves using Linux LVM. This guarantees a consistent snapshot while requiring very minimal downtime on your master.
Set innodb max dirty pages percent to zero on the master MySQL server. This will force MySQL to write all the pages to the disk which will significantly speed up the restart.
set global innodb_max_dirty_pages_pct = 0;
To monitor the number of dirty pages run the command
mysqladmin ext -i10 | grep dirty
Once the number stop decreasing you have reach the point to continue. Next reset the master to clear the old bin logs / relay logs:
RESET MASTER;
Execute lvdisplay to get LV Path
lvdisplay
Output will look like this
--- Logical volume ---
LV Path /dev/vg_mysql/lv_data
LV Name lv_data
VG Name vg_mysql
Shutdown the master database with command
service mysql stop
Next take a snaphot, mysql_snapshot will be the new logical volume name. If binlogs are place on the OS drive those need to be snapshot as well.
lvcreate --size 10G --snapshot --name mysql_snapshot /dev/vg_mysql/lv_data
Start master again with command
service mysql start
Restore dirty pages setting to the default
set global innodb_max_dirty_pages_pct = 75;
Run lvdisplay again to make sure the snapshot is there and visible
lvdisplay
Output:
--- Logical volume ---
LV Path /dev/vg_mysql/mysql_snapshot
LV Name mysql_snapshot
VG Name vg_mysql
Mount the snapshot
mkdir /mnt/mysql_snapshot
mount /dev/vg_mysql/mysql_snapshot /mnt/mysql_snapshot
If you have an existing MySQL slave running you need to stop it
service mysql stop
Next you need to clear MySQL data folder
cd /var/lib/mysql
rm -fr *
Back to master. Now rsync the snapshot to the MySQL slave
rsync --progress -harz /mnt/mysql_snapshot/ targethostname:/var/lib/mysql/
Once rsync has completed you may unmount and remove the snapshot
umount /mnt/mysql_snapshot
lvremove -f /dev/vg_mysql/mysql_snapshot
Create replication user on the master if the old replication user doesn't exist or password is unknown
GRANT REPLICATION SLAVE on *.* to 'replication'#'[SLAVE IP]' identified by 'YourPass';
Verify that /var/lib/mysql data files are owned by the mysql user, if so you can omit the following command:
chown -R mysql:mysql /var/lib/mysql
Next record the binlog position
ls -laF | grep mysql-bin
You will see something like
..
-rw-rw---- 1 mysql mysql 1073750329 Aug 28 03:33 mysql-bin.000017
-rw-rw---- 1 mysql mysql 1073741932 Aug 28 08:32 mysql-bin.000018
-rw-rw---- 1 mysql mysql 963333441 Aug 28 15:37 mysql-bin.000019
-rw-rw---- 1 mysql mysql 65657162 Aug 28 16:44 mysql-bin.000020
Here the master log file is the highest file number in sequence and bin log position is the file size. Record these values:
master_log_file=mysql-bin.000020
master_log_post=65657162
Next start the slave MySQL
service mysql start
Execute change master command on the slave by executing the following:
CHANGE MASTER TO
master_host="10.0.0.12",
master_user="replication",
master_password="YourPass",
master_log_file="mysql-bin.000020",
master_log_pos=65657162;
Finally start the slave
SLAVE START;
Check slave status:
SHOW SLAVE STATUS;
Make sure Slave IO is running and there are no connection errors. Good luck!
I recently wrote this on my blog which is found here... There are few more details there but the story is the same.
http://www.juhavehnia.com/2015/05/rebuilding-mysql-slave-using-linux-lvm.html
I created a GitHub repo with an script to solve this problem quickly. Just change a couple variables and run it (First, the script creates a backup of your database).
I hope this help you (and others people too).
How to Reset (Re-Sync) MySQL Master-Slave Replication
sometimes you just need to give the slave a kick too
try
stop slave;
reset slave;
start slave;
show slave status;
quite often, slaves, they just get stuck guys :)
We are using master-master replication technique of MySQL and if one MySQL server say 1 is removed from the network it reconnects itself after the connection are restored and all the records that were committed in the in the server 2 which was in the network are transferred to the server 1 which has lost the connection after restoration.
Slave thread in the MySQL retries to connect to its master after every 60 sec by default. This property can be changed as MySQL ha a flag "master_connect_retry=5" where 5 is in sec. This means that we want a retry after every 5 sec.
But you need to make sure that the server which lost the connection show not make any commit in the database as you get duplicate Key error Error code: 1062