Did you get the following message/alert from cpanel?
check_mysql has determined that there are corrupted database tables
First, you want to rule out that you’re not having serious server issues like a failing HD (test with smartctl) or OS/kernel crashes (review OS logs). To see the exact database causing the issue you will want to review the mysql log. On a cpanel server, this will be found in /var/lib/mysql/
The error you’re looking for will look something like this:
2016-03-15 17:14:26 30634 [ERROR] /usr/sbin/mysqld: Table ‘./eximstats/failures’ is marked as crashed and should be repaired
If you see anything related to /eximstats/ you can repair the database/table or simple drop it and re-create it with the below command:
mysqladmin drop eximstats
mysqladmin create eximstats
mysql eximstats < /usr/local/cpanel/etc/eximstats_db.sql
Alternatevly, you can also do it from the mysql interface like this:
mysql> use eximstats
mysql> delete from sends;
mysql> delete from smtp;
mysql> delete from failures;
mysql> delete from defers;
Once done, restart mysql (with something like: service mysql restart) and you should be all set.