The full backup strategy produces large backups which include all the archived files (like instrumented class files source code from code coverage) from the builds, but the ConfigOnly strategy loses all build history. An intermediate strategy that includes the basic build history without the large binary files would preserve

• jobs/**/config.xml
• jobs/**/nextBuildNumber
• jobs/**/builds/legacyIds
• jobs/**/builds/**/*.xml
• jobs/**/builds/**/injectedEnvVars.txt
• jobs/**/builds/**/log

Or maybe a configurable set of patterns to exclude like

• jobs/**/builds/**/*.jar
• jobs/**/builds/**/*.class
• jobs/**/builds/**/*.java
• jobs/**/builds/**/*.so
• jobs/**/builds/**/*. {cpp,c,C,h,hxx,cs}
• jobs/**/builds/**/*.exe
• jobs/**/builds/**/*.zip
• jobs/**/builds/**/*.tar
• jobs/**/builds/**/*.tar. {gz,gzip,bzip2,bz2,Z}