http://localhost:8080/plugin/disk-usage/ does not say how many minutes between calculation. It just says, "Disk usage is calculated each minutes."

DiskUsagePlugin/index.jelly has ${it.COUNT_INTERVAL_MINUTES} where that number should be. I would guess this bug occured in http://fisheye.jenkins-ci.org/changelog/Hudson/?cs=16498 when COUNT_INTERVAL_MINUTES was moved from DiskUsagePlugin to DiskUsageThread.

However, I don't know how to fix it. ${DiskUsageThread.COUNT_INTERVAL_MINUTES} doesn't seem to work. (I don't understand what jelly is doing here.)

I didn't make this bug's priority trivial because http://wiki.jenkins-ci.org/display/JENKINS/Disk+Usage+Plugin says that the interval is every 15 minutes, so when it failed to calculate after 15 minutes, I had to go get the source and figure out what was wrong. It looks like 60 minutes in the source, and it did succeed in calculating after that period. I'll try to update the wiki, but I don't have the more important screen-shot handy.

This looks like a great plugin, by the way.