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I have a MySQL 5.7 running on a Centos 6. I enabled Binary Logging and didn't provide any custom value for the maximum size of Binary Log in my configuration file. By default, the parameter max_binlog_size = 1073741824 which is equivalent to 1GB. This means, once a binary log reaches the size of 1GB, a new file should be created.

I observed in my server that all the binary log files are of different sizes with lot of contrast like 200GB, 165GB, 4GB etc...

Why does this happen when the maximum size is 1GB for a binary log file? Is it necessary to mention even the default maximum size explicitly in the configuration file?

Yashwanth Aluru
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1 Answers1

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If a write to the binary log causes the current log file size to exceed the value of this variable, the server rotates the binary logs (closes the current file and opens the next one). The minimum value is 4096 bytes. The maximum and default value is 1GB.

A transaction is written in one chunk to the binary log, so it is never split between several binary logs. Therefore, if you have big transactions, you might see binary log files larger than max_binlog_size.

If max_relay_log_size is 0, the value of max_binlog_size applies to relay logs as well.

https://dev.mysql.com/doc/refman/5.7/en/replication-options-binary-log.html

samar ranjan Nayak
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