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Displaying posts with tag: Replication/Slave/Master (reset)
MySQL blank users preventing slave I/O connection?

Recently I have encountered a weird simple issue with starting Slave server.

So created user as tried to run change master:

2017-10-30 14:03:59 DEBUG    Running -> /home/shahriyar.rzaev/XB_TEST/server_dir/PS231017-percona-server-5.6.37-82.2-linux-x86_64-debug/bin/mysql -A -uroot -S/home/shahriyar.rzaev/XB_TEST/server_dir/PS231017-percona-server-5.6.37-82.2-linux-x86_64-debug/socket.sock --force test -e 
'select @@port'
2017-10-30 14:03:59 DEBUG    Running -> /home/shahriyar.rzaev/XB_TEST/server_dir/PS231017-percona-server-5.6.37-82.2-linux-x86_64-debug/bin/mysql -A -uroot -S/home/shahriyar.rzaev/XB_TEST/server_dir/PS231017-percona-server-5.6.37-82.2-linux-x86_64-debug/socket.sock --force test -e 
"CREATE USER 'repl'@'%' IDENTIFIED BY 'Baku12345'"
2017-10-30 14:03:59 DEBUG    Running -> /home/shahriyar.rzaev/XB_TEST/server_dir/PS231017-percona-server-5.6.37-82.2-linux-x86_64-debug/bin/mysql -A -uroot …
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Comprehensive guide to installing PXC on CentOS 7

Recently want to install Percona XtraDB Cluster + HAProxy + KeepAlived on CentOS 7, but could not find any all-in-one guide. So decided to write down all steps necessary for getting started and running HA solution using Open Source projects. Nowadays high availability is one of the main concerns faced by big and small companies.Minimum wasting of time (downtime per year), sustainably working of infrastructure and etc. is the main mission for all companies that they are trying to achieve.There are different approaches to this mission. One of them as large companies did, to buy expensive software and support from vendors. But small companies could not go through these steps. The true power of Open Source comes up at these moments.You can build your own High Availability solution using free but yet powerful Open Source projects. In this article we will show you how to achieve Database Clustering and Load Balancing. We will use:

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Error reading GTIDs from binary log: -1

Wonder how MySQL Slave server will act, when disk full condition occurs? Before in our articles we use only single MySQL server. Now think about replication topology, where slave server has problem with full partition. Firstly we will enable Binary Log/GTID on Slave side and will ensure that the changes also applied to binary log on Slave side:

      server_id = 2 
      log_bin = /opt/mysql/datadir/mysql-bin 
      log_bin_index = /opt/mysql/datadir/mysql-bin 
      expire_logs_days = 14 
      sync_binlog = 1 
      binlog_format = row 
      relay_log = /opt/mysql/datadir/mysql-relay-bin 
      log_slave_updates = 1 
      read_only = 1 
      gtid-mode = on 
      enforce-gtid-consistency = true 
      master-info-repository = TABLE 
      relay-log-info-repository = TABLE 
      slave-parallel-workers = 15 
      binlog-checksum = CRC32 
      master-verify-checksum = 1 
      slave-sql-verify-checksum = 1 …
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Change binary log and relay log location to /home? SELinux issue

Recently in my slave server there was a full disk error because of the huge size of binary logs.Which is lead to critical error and BUG report which is still stays as open:

So the issue was a partition problem which in partitioning stage haven’t been specified for “/” (root) filesystem. But in “/home” there were left enough space.
The quick decision was to change binary and relay log location(path) to “/home”.
But there was a great challenge to get real working slave again.

Now we will explore all steps in our test virtual machine.
Test conditions for me:

1. CentOS 6.5 (x86_64) (both master and slave)
2. MySQL 5.6.19 GA (from official yum repo) (both master and slave)

Master my.cnf:

server_id                      = …
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How to Solve Replication lag? quick solution

This topic is not for all situations but in my situation it helps.
The problem is with Slave is lagging behind master in very large numbers and the relay logs are continously growing.

Slave is using:

Relay_Log_File: mysql-relay-bin.000031

But in folder where relay log resides, was created up to:


And it is continously growing.
So what i decide to do, again step-by-step i edited my.cnf file as follows:

1. I have 13 database so give to slave paralel workers 13:
slave-parallel-workers = 13

2. Disabled sync_binlog:
sync_binlog = 0

3. Changed at_trx_commit from 1 to 0:
innodb_flush_log_at_trx_commit = 0

4. Gave log_at_timeout (only from 5.6.6>) to 10:
innodb_flush_log_at_timeout = 10

5. Disabled slow query log( or commented out)

So …

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Showing entries 1 to 5