Rename OBD to Health (#10842)

Also, Remove thread stats and openfds from the health report 
as we already have process stats and numfds

pkg/disk/health.go

@@ -0,0 +1,165 @@
+/*
+ * MinIO Cloud Storage, (C) 2020 MinIO, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package disk
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/dustin/go-humanize"
+	"github.com/montanaflynn/stats"
+)
+
+// Latency holds latency information for write operations to the drive
+type Latency struct {
+	Avg          float64 `json:"avg_secs,omitempty"`
+	Percentile50 float64 `json:"percentile50_secs,omitempty"`
+	Percentile90 float64 `json:"percentile90_secs,omitempty"`
+	Percentile99 float64 `json:"percentile99_secs,omitempty"`
+	Min          float64 `json:"min_secs,omitempty"`
+	Max          float64 `json:"max_secs,omitempty"`
+}
+
+// Throughput holds throughput information for write operations to the drive
+type Throughput struct {
+	Avg          float64 `json:"avg_bytes_per_sec,omitempty"`
+	Percentile50 float64 `json:"percentile50_bytes_per_sec,omitempty"`
+	Percentile90 float64 `json:"percentile90_bytes_per_sec,omitempty"`
+	Percentile99 float64 `json:"percentile99_bytes_per_sec,omitempty"`
+	Min          float64 `json:"min_bytes_per_sec,omitempty"`
+	Max          float64 `json:"max_bytes_per_sec,omitempty"`
+}
+
+// GetHealthInfo about the drive
+func GetHealthInfo(ctx context.Context, drive, fsPath string) (Latency, Throughput, error) {
+
+	// Create a file with O_DIRECT flag, choose default umask and also make sure
+	// we are exclusively writing to a new file using O_EXCL.
+	w, err := OpenFileDirectIO(fsPath, os.O_CREATE|os.O_WRONLY|os.O_EXCL, 0666)
+	if err != nil {
+		return Latency{}, Throughput{}, err
+	}
+
+	defer func() {
+		w.Close()
+		os.Remove(fsPath)
+	}()
+
+	blockSize := 4 * humanize.MiByte
+	fileSize := 256 * humanize.MiByte
+
+	latencies := make([]float64, fileSize/blockSize)
+	throughputs := make([]float64, fileSize/blockSize)
+
+	data := AlignedBlock(blockSize)
+
+	for i := 0; i < (fileSize / blockSize); i++ {
+		if ctx.Err() != nil {
+			return Latency{}, Throughput{}, ctx.Err()
+		}
+		startTime := time.Now()
+		if n, err := w.Write(data); err != nil {
+			return Latency{}, Throughput{}, err
+		} else if n != blockSize {
+			return Latency{}, Throughput{}, fmt.Errorf("Expected to write %d, but only wrote %d", blockSize, n)
+		}
+		latencyInSecs := time.Since(startTime).Seconds()
+		latencies[i] = latencyInSecs
+	}
+
+	// Sync every full writes fdatasync
+	Fdatasync(w)
+
+	for i := range latencies {
+		throughput := float64(blockSize) / latencies[i]
+		throughputs[i] = throughput
+	}
+
+	var avgLatency float64
+	var percentile50Latency float64
+	var percentile90Latency float64
+	var percentile99Latency float64
+	var minLatency float64
+	var maxLatency float64
+
+	var avgThroughput float64
+	var percentile50Throughput float64
+	var percentile90Throughput float64
+	var percentile99Throughput float64
+	var minThroughput float64
+	var maxThroughput float64
+
+	if avgLatency, err = stats.Mean(latencies); err != nil {
+		return Latency{}, Throughput{}, err
+	}
+	if percentile50Latency, err = stats.Percentile(latencies, 50); err != nil {
+		return Latency{}, Throughput{}, err
+	}
+	if percentile90Latency, err = stats.Percentile(latencies, 90); err != nil {
+		return Latency{}, Throughput{}, err
+	}
+	if percentile99Latency, err = stats.Percentile(latencies, 99); err != nil {
+		return Latency{}, Throughput{}, err
+	}
+	if maxLatency, err = stats.Max(latencies); err != nil {
+		return Latency{}, Throughput{}, err
+	}
+	if minLatency, err = stats.Min(latencies); err != nil {
+		return Latency{}, Throughput{}, err
+	}
+	l := Latency{
+		Avg:          avgLatency,
+		Percentile50: percentile50Latency,
+		Percentile90: percentile90Latency,
+		Percentile99: percentile99Latency,
+		Min:          minLatency,
+		Max:          maxLatency,
+	}
+
+	if avgThroughput, err = stats.Mean(throughputs); err != nil {
+		return Latency{}, Throughput{}, err
+	}
+	if percentile50Throughput, err = stats.Percentile(throughputs, 50); err != nil {
+		return Latency{}, Throughput{}, err
+	}
+	if percentile90Throughput, err = stats.Percentile(throughputs, 90); err != nil {
+		return Latency{}, Throughput{}, err
+	}
+	if percentile99Throughput, err = stats.Percentile(throughputs, 99); err != nil {
+		return Latency{}, Throughput{}, err
+	}
+	if maxThroughput, err = stats.Max(throughputs); err != nil {
+		return Latency{}, Throughput{}, err
+	}
+	if minThroughput, err = stats.Min(throughputs); err != nil {
+		return Latency{}, Throughput{}, err
+	}
+
+	t := Throughput{
+		Avg:          avgThroughput,
+		Percentile50: percentile50Throughput,
+		Percentile90: percentile90Throughput,
+		Percentile99: percentile99Throughput,
+		Min:          minThroughput,
+		Max:          maxThroughput,
+	}
+
+	return l, t, nil
+}