4 ms·

I would love to hear how this happened.

• jmts 9y ago
  At a previous job, I had to investigate a similar issue where some online exams were being terminated early. The overall scheme worked out something like this: 1. students connect to the online system 2. load balancers assign each connection to a server from a pool of 8 or so 3. students start the test 4. a single server responsible for monitoring test duration, checks all open test instances, and terminates those that have exceeded the test time limit The issue ended up being that a single one of the load balanced servers had its time set slow. That meant that when the terminator server came along, the students had their test end according to the time delta between the server assigned their connection, and the terminator server. Amusingly, it took some time to convince the sysadmin to check their times - they were convinced that they'd manually corrected all the system times after the last power outage...
  • willbw 9y ago
    Thanks for this, interesting stuff!