</RollingFile>
		<Rewrite name="AppFile">
			<AppenderRef ref="AppRollingFile" />
			<ErrorToWarnRewritePolicy loggers="org.apache.fontbox,org.apache.pdfbox,org.apache.poi" />
		</Rewrite>
		<RollingFile name="StatsFile" fileName="${log.file.basedir}/fess-urls.log"
			filePattern="${log.file.basedir}/fess-urls${backup.date.suffix}-%i.log.gz">
			<PatternLayout>
				<Pattern>${stats.log.pattern}</Pattern>
			</PatternLayout>
			<Policies>

	return readDriveStats(fmt.Sprintf("/sys/dev/block/%v:%v/stat", major, minor))
}

func readDriveStats(statsFile string) (iostats IOStats, err error) {
	stats, err := readStat(statsFile)
	if err != nil {
		return IOStats{}, err
	}
	if len(stats) < 11 {
		return IOStats{}, fmt.Errorf("found invalid format while reading %v", statsFile)
	}
	// refer https://www.kernel.org/doc/Documentation/block/stat.txt
	iostats = IOStats{