It is logging slow requests... 320 Meg since April 19.
Assuming an average log message length of 100 bytes, this amounts to between two and three logs per second, so this could conceivably be the bottle neck. Could you chop off the last 10 megs or so, make them available on www.wikipedia.com/tarballs, and switch off the logging?
Axel
wikitech-l@lists.wikimedia.org