code: public EnvironmentConfig setGcFileMinAge(int minAge) throws InvalidSettingException {
          if (minAge < 1) {
              throw new InvalidSettingException("Invalid file minimum age: " + minAge);
          }
          return setSetting(GC_MIN_FILE_AGE, minAge);
      }
docs: Returns the minimum age of a {@code Log} file (.xd file) to consider it for cleaning by the database garbage
  collector. The age of the last (the newest, the rightmost) {@code Log} file is {@code 0}, the age of previous
  file is {@code 1}, etc. Default value is {@code 2}. The age cannot be less than {@code 1}.
  <p>Mutable at runtime: yes
  
  @param minAge minimum age of .xd file to consider it for cleaning by the database garbage collector
  @return this {@code EnvironmentConfig} instance
  @throws InvalidSettingException minAge is less than {@code 1}.