I think I can sketch out a few details.

1. The first thing is that this is not a medical emergency. I'm saying that for my own peace of mind. System administration under duress is no fun at all.

2. The builds are still there. They don't disappear. They just aren't seen by the webpage. We are not alone in this. It has happened before.

http://jenkins.361315.n4.nabble.com/JIRA-JENKINS-11938-Jenkins-loses-builds-when-restarted-td4124991.html

3. The problem may be in the reading of an XML file. The solution I've gleaned so far is that instead of creating another build, I could log in and press:
 
"Reload Configuration from Disk"

Or I could just try restarting.

4. This didn't happen on the older server. It won't last forever on this one.

5. God knows, somebody will come up with a better answer than I can. But since you're all looking at me at this moment, I say this: "Don't panic. We still know where our towel is."


Chris