cachevalue.Opts{ReturnLastGood: true},
		loadNodesUpDown)
}

type driveIOStatMetrics struct {
	readsPerSec    float64
	readsKBPerSec  float64
	readsAwait     float64
	writesPerSec   float64
	writesKBPerSec float64
	writesAwait    float64
	percUtil       float64
}

// storageMetrics - cached storage metrics.
type storageMetrics struct {

	if ioStats.readsPerSec > 0 {
		m.Set(driveReadsAwait, ioStats.readsAwait, labels...)
	}

	m.Set(driveWritesPerSec, ioStats.writesPerSec, labels...)
	m.Set(driveWritesKBPerSec, ioStats.writesKBPerSec, labels...)
	if ioStats.writesPerSec > 0 {
		m.Set(driveWritesAwait, ioStats.writesAwait, labels...)
	}

	m.Set(drivePercUtil, ioStats.percUtil, labels...)
}