func (z *erasureServerPools) ListBuckets(ctx context.Context, opts BucketOptions) (buckets []BucketInfo, err error) {
	if opts.Cached {
		listBucketsCache.InitOnce(time.Second,
			cachevalue.Opts{ReturnLastGood: true, NoWait: true},
			func(ctx context.Context) ([]BucketInfo, error) {
				ctx, cancel := context.WithTimeout(ctx, 5*time.Second)
				defer cancel()

				buckets, err = z.s3Peer.ListBuckets(ctx, opts)

	sysCPUSystem    = "system"
	sysCPUUser      = "user"
)

var (
	sysCPUAvgIdleMD   = NewGaugeMD(sysCPUAvgIdle, "Average CPU idle time")
	sysCPUAvgIOWaitMD = NewGaugeMD(sysCPUAvgIOWait, "Average CPU IOWait time")
	sysCPULoadMD      = NewGaugeMD(sysCPULoad, "CPU load average 1min")
	sysCPULoadPercMD  = NewGaugeMD(sysCPULoadPerc, "CPU load average 1min (percentage)")
	sysCPUNiceMD      = NewGaugeMD(sysCPUNice, "CPU nice time")

	interfaceTxBytes  MetricName = "tx_bytes"
	interfaceTxErrors MetricName = "tx_errors"

	// cpu stats
	cpuUser       MetricName = "user"
	cpuSystem     MetricName = "system"
	cpuIOWait     MetricName = "iowait"
	cpuIdle       MetricName = "idle"
	cpuNice       MetricName = "nice"
	cpuSteal      MetricName = "steal"
	cpuLoad1      MetricName = "load1"
	cpuLoad5      MetricName = "load5"
	cpuLoad15     MetricName = "load15"

| `minio_node_cpu_avg_idle_max`        | CPU idle time (max).                       |
| `minio_node_cpu_avg_iowait`          | CPU ioWait time.                           |
| `minio_node_cpu_avg_iowait_avg`      | CPU ioWait time (avg).                     |
| `minio_node_cpu_avg_iowait_max`      | CPU ioWait time (max).                     |
| `minio_node_cpu_avg_nice`            | CPU nice time.                             |

| `minio_system_cpu_avg_idle`   | Average CPU idle time. <br><br>Type: gauge              | `server` |
| `minio_system_cpu_avg_iowait` | Average CPU IOWait time. <br><br>Type: gauge            | `server` |
| `minio_system_cpu_load`       | CPU load average 1min. <br><br>Type: gauge              | `server` |