Logs for Machines

The binary logs are used for backup and replication.

The server can be told to record each and every MySQL transaction in a specially formatted log-file called the binary log. The binary log is used for database replication between servers but it is essentially also a backup tool, as it gives us the possibility to restore the exact state of a database table of any given point in the past by reversing all transactions found in the binary log.


# MariaDB Server version 10.2.6


# Binary Log
# https://mariadb.com/kb/en/mariadb/binary-log/

# The full path of the binary log file names, excluding the extension. Its value
# is derived from the rules specified in log_bin system variable.
# Default: as set by "log_bin"
#log_bin_basename = /var/log/mysql/mariadb-bin
log_bin_basename = Aiken

# Whether binary logging is enabled or not. If the --log-bin option is used,
# log_bin will be set to ON, otherwise it will be OFF. If no name option is
# given for --log-bin, datadir/'log-basename'-bin or 'datadir'/mysql-bin will be
# used (the latter if --log-basename is not specified). We strongly recommend
# you use either --log-basename or specify a filename to ensure that replication
# doesn't stop if the real hostname of the computer changes. The name option can
# optionally include an absolute path. If no path is specified, the log will be
# written to the data directory.
# Default: OFF
log_bin	= /var/lib/mysql/Aiken-bin

# File that holds the names for last binlog files.
# Default: Same name as the binary log files, with the extension .index
#log_bin_index = /var/log/mysql/Aiken-bin.index

# If the binary log exceeds this size after a write, the server rotates it by
# closing it and opening a new binary log. Single transactions will always be
# stored in the same binary log, so the server will wait for open transactions
# to complete before rotating. This figure also applies to the size of relay
# logs if max_relay_log_size is set to zero.
# Default: 1073741824 (1GB)
max_binlog_size = 100M

# Determines whether replication is row-based, statement-based or mixed. Be
# careful of changing the binary log format when a replication environment is
# already running.
# See https://mariadb.com/kb/en/binary-log-formats/
# Default: MIXED
#binlog-format = MIXED

# Number of days after which the binary log will be automatically removed. O
# means no automatic removal. When using replication, should always be set
# higher than the maximum lag by any slave.
# Default: 0
expire_logs_days = 21

# Number of events after the the binary log file is synchronized to disk. If 0
# the operating system handles flushing the file to disk. 1 is the safest, but
# slowest, choice, since the file is flushed after each write. If autocommit is
# enabled, there is one write per statement, otherwise there's one write per
# transaction. If the disk has cache backed by battery, synchronization will be
# fast and a more conservative number can be chosen.
# Default: 0
#sync_binlog = 1

Notable settings

  • Same as before, set log_bin to a unique distinguishable and identifiable name across all past, present and future instances of your database servers.

  • We set the max_binlog_size to a more manageable size in case they have to be moved across slower networks or media.

  • We set expire_logs_days to a value that lets us survive a major outage for up to three weeks.