I guess I need to upgrade my server since it is not suitable for 24/7 operation. After running it for months, it almost always leads to various hardware problems. Also, I need to become a better system admin. A while ago, /var became full, and RDBMS servers refused to write on /var. I spotted the cause and fixed it. On Wed, Jun 18, 2014 at 6:06 PM, crocket <crockabiscuit@gmail.com> wrote:

A lot of images and attachments went missing after xwiki upgrade. However, after rebooting my machine, xwiki was magically fixed.

I guess something made PostgreSQL instance refuse to serve its contents and restarting the instance solved the problem.