MySQL can keep a so-called binary log of transactions, which keeps track of all updates to the database. It is used for database restoration and replication.
The logs can grow very quickly in size. At the time of writing, my logs take up around 68G.
I use the database in question as a dump for backups taken from various other servers, so it is not necessary for me to keep transaction logs.
How to turn off binary logging
Edit your my.cnf file and comment out the log-bin option. Also make sure that expire_log_days option is missing or commented out.
...
#log-bin
...
#expire_logs_days = 10
...
Then restart mysql.
How to delete the binary logs
On Gentoo, the logs are located in /var/lib/mysql.
If you have not configured a custom basename for the log files, it is likely they are stored using your domain name, e.g. localhost-bin.000001. I believe older versions of MySQL used “mysql” as the basename, so look for mysql-bin.000001. There will also be an index file with a .index extension.
bpc ~ # cd /var/lib/mysql
bpc mysql # ls
auto.cnf mysqld-bin.000278 mysqld-bin.000301 mysqld-bin.000324
...cut... mysqld-bin.000279 mysqld-bin.000302 mysqld-bin.000325
...cut... mysqld-bin.000280 mysqld-bin.000303 mysqld-bin.000326
ibdata1 mysqld-bin.000281 mysqld-bin.000304 mysqld-bin.000327
ib_logfile0 mysqld-bin.000282 mysqld-bin.000305 mysqld-bin.000328
ib_logfile1 mysqld-bin.000283 mysqld-bin.000306 mysqld-bin.000329
...cut... mysqld-bin.000284 mysqld-bin.000307 mysqld-bin.000330
...cut... mysqld-bin.000285 mysqld-bin.000308 mysqld-bin.000331
...cut... mysqld-bin.000286 mysqld-bin.000309 mysqld-bin.000332
...cut... mysqld-bin.000287 mysqld-bin.000310 mysqld-bin.000333
mysql mysqld-bin.000288 mysqld-bin.000311 mysqld-bin.000334
mysqld-bin.000266 mysqld-bin.000289 mysqld-bin.000312 mysqld-bin.000335
mysqld-bin.000267 mysqld-bin.000290 mysqld-bin.000313 mysqld-bin.000336
mysqld-bin.000268 mysqld-bin.000291 mysqld-bin.000314 mysqld-bin.index
mysqld-bin.000269 mysqld-bin.000292 mysqld-bin.000315 performance_schema
mysqld-bin.000270 mysqld-bin.000293 mysqld-bin.000316 ...cut...
mysqld-bin.000271 mysqld-bin.000294 mysqld-bin.000317 ...cut...
mysqld-bin.000272 mysqld-bin.000295 mysqld-bin.000318 ...cut...
mysqld-bin.000273 mysqld-bin.000296 mysqld-bin.000319 ...cut...
mysqld-bin.000274 mysqld-bin.000297 mysqld-bin.000320 ...cut...
mysqld-bin.000275 mysqld-bin.000298 mysqld-bin.000321
mysqld-bin.000276 mysqld-bin.000299 mysqld-bin.000322
mysqld-bin.000277 mysqld-bin.000300 mysqld-bin.000323
(The ...cut... are my databases that I’ve removed from the listing).
To delete the logs, do the following in mysql, replacing mysqld-bin.000336 with the oldest log that you’d like to keep:
purge binary logs to 'mysqld-bin.000336';
This will get rid of all logs from .000001 to .000336.
bpc mysql # ls
auto.cnf ib_logfile1 mysql ...cut...
...cut... ...cut... mysqld-bin.000336 ...cut...
...cut... ...cut... mysqld-bin.index ...cut...
ibdata1 ...cut... performance_schema ...cut...
ib_logfile0 ...cut... ...cut...
