It is very happy to come back and write stuff here, really. Yesterday, few hours after I noticed an observable slow down when visiting His Story, I was told that for some reason my blog had led its hosting server to a heavy processor load, up to 50%. HS was shut down at the moment.
HS is built using WordPress at its current version 2.0.1. By deactivating all the plugins I have installed, it turned out that they were not the reason causing the problem. Very soon, I found that the directories under wp-content/cache contained huge amount of temporary files, which seemed to be the cached pages of HS. It was slow when gftp was fetching the file names under these directories. Since they were automatically generated files which were not important, I removed all of them. Right after that, HS was responding again.
By searching through WordPress official forums, I found that its cache mechanism does not do the clean job automatically. Although it aims for speeding up the execution of PHP scripts, but due to the large amount of cached file, PHP’s file traversing function makes the website slow again. To disable, simply add following line in wp-config.php under the root directory where WordPress is located:
define('DISABLE_CACHE', true);
Hope this issue can be solved in next release of WordPress.
Reference:
http://wordpress.org/support/topic/52452?replies=17#post-330443