MySql generates files in /var/lib/mysql

Question

We have noticed that we run out of space on one of our machines that is running Mysql 5.5.37 (InnoDb)

Mysql seems to be generating several ~1.1GB files per day with the name pattern 0.0001234 (increasing number) in the /var/lib/mysql folder.

• What are those files?
• Can they be deleted?
• Can we configure mysql to write them to a different location?

Answer 1

To avoid having to do the purge periodically, set this:

expire_logs_days = 7

in my.cnf. That will keep the binlogs purged down to 7 days' worth.

See also binlog_expire_logs_seconds in MySQL 8.0.

Answer 2

Turns out these were binlogs.

The setting log_bin=0 does not disable them but simply sets the file-name-format to 0.\d+

We deleted the present logs with PURGE BINARY LOGS to 'lastFileName', then disabled the generation by commenting out all bin_log related entries in the my.cnf.