Since updating timestamper-plugin to version 1.13, Jenkins throws IOExceptions for "Too many open files" after some hours and Jenkins gets unresponsive.

Checked with Linux's "lsof -u jenkins" command we see a lot of open files with pattern

/var/lib/jenkins/jobs/*/builds/*/timestamper/timestamps

The number of open files of this pattern increases over time until the limit is reached.

A Jenkins restart frees the file handles and makes Jenkins responsive again - until open file limits are reached again.

A downgrade of timestamper-plugin to version 1.12 solved the issue for us.