I am suffering from performance problems. Delivery of pages can take up to 80 seconds. See

The CPU is kept busy by the http process.

Looking into the ACCESS log nothing obvious caught my eye. The ERROR log is much more interesting. There are thousands of entries like this:

WARNING MoinMoin.util.filesys:110 mkdir(('...\\\\data\\\\cache\\\\aplwiki\\\\pagegroups\\\\__lock__\\\\write_lock',), {}) -> access denied. retrying...

What is going on here?! Advice is welcome.