On February 20th for some reason or another after using a utility to clean up this website from junk code, each and every page and post was deleted! Whether it was a bug in the utility, or perhaps a malicious attack by a hacker, I cannot say. I was able to restore most of the pages and posts from a backup file, but I lost several days work, 4 posts including 3 whole books, many editions on other pages and posts, and recent comments. This left me discouraged. But I can only blame myself for not making a more recent backup of the database after so much work.
I may switch to Drupal which I hear has much better security against malicious attacks. At this time, I am experimenting with a Drupal installation on http://gakudo-jpn.net/ One really cool thing that Drupal has is built in ability to publish books into chapters in separate pages! WordPress cannot do that so easily. It needs a third party plugin called Multipage, what this site is using. Third party plugins are subject to bugs that the WordPress developer have no control over.
I believe a bug in a plugin called WP-Optimize was the culprit. I uninstalled it.
Another WordPress plugin I uninstalled is WordFence. I find this plugin next to useless. It never really protected this site from malicious hacker code, it only told me about being hacked after the fact! And usually by then the site was infected so bad I could not even view it. Moreover, WordFence filled the database with junk! After removing WordFence, the database sql file was reduced from 60 megabytes to only 12!
I also got rid of WordPress Online Backup. I think it’s better to export the database directly from MyPHPAdmin in Cpanel. WordPress Online Backup took a lot of resources and slowed down the site.