Web Server Database

     Mariadb, the database that is used to provide SQL service for most web apps requiring it (a handful use postgresql) hung when some internal process failed to remove a lock and everything else piled up behind it.  I could not restart it with either systemd or mysqladmin, and even a regular kill signal did not work, kill -9 eventually did but even the response to that was delayed by several minutes.  There was nothing in either the kernel logs or the mariadb logs that would provide a clue as to why this happened and it is a failure mode I have not seen before.

     Because mariadb was not shut-down properly, database corruption is a possibility.  Accordingly, I am running mariadb-repair –all-databases to check for and repair any inconsistencies. This may slow response slightly for the next hour or so.