Update: I have posted a reply and a possible solution to this problem, here.
As you may know, i’m a keen FOSS (Free Open Source Software) advocate and avid user. As such, it pains me to complain about the hard work, time and passion FOSS communities put in to their software, but this time – I have to rant!

This site, like many others, runs MySQL; the Free (both libre and as in beer) Relational Database Management System (RDBMS). MySQL by all merits is a good piece of software. It is lightweight (small memory footprint in comparison to Oracle for example), provides many of the features that other RDBMSs have to offer (stored procedures, views etc); except however, it has increasingly become unstable on this server (and it’s not as though we have 1000 hits a minute…). The main issues seem to be with locking and for whatever reason, MySQL falls over. Shutting it down with the init scripts doesn’t help, and I therefore have to `sudo killall mysql` which is a horrible way to bring a database down – data corruption is likely to occur. The error provided in /var/log/mysql.err is as follows:

#061003 21:44:36 InnoDB: Unable to open the first data file
#InnoDB: Error in opening ./ibdata1
#061003 21:44:36 InnoDB: Operating system error number 11 in a file operation.
#InnoDB: Error number 11 means 'Resource temporarily unavailable'.
#InnoDB: Some operating system error numbers are described at
#InnoDB: http://dev.mysql.com/doc/mysql/en/Operating_System_error_codes.html
#InnoDB: Could not open or create data files.

This doesn’t say much, as it seems this error occurs when the server attempts to shut down (or when its init script is called to shut it down), as to its cause or solution I am out of luck. The MySQL channel on freenode.net didn’t seem to have any idea, nor did the MySQL official forums. For now, I am going to investigate the use of PostgreSQL with Wordpress (apparently, it isn’t possible. Wordpress only has MySQL support); if I can provide support for Postgres I will migrate immediately! Not only is Postgres more reliable (from my investigation), it also has more features (bindings for procedures any languages such as Python and Perl) and is of course much more mature – highly recommended from my minor usage.
(Google Index update – searching for ‘placid’ returns this site, on average, as the 17th result – that’s page two!)