Implement oboard diagnostics admin API (#9024)

- Implement a graph algorithm to test network bandwidth from every 
  node to every other node
- Saturate any network bandwidth adaptively, accounting for slow 
  and fast network capacity
- Implement parallel drive OBD tests
- Implement a paging mechanism for OBD test to provide periodic updates to client
- Implement Sys, Process, Host, Mem OBD Infos

cmd/obdinfo_other.go

@@ -0,0 +1,86 @@
+// +build !freebsd
+
+/*
+ * 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 cmd
+
+import (
+	"context"
+	"strings"
+
+	"github.com/minio/minio/pkg/madmin"
+	diskhw "github.com/shirou/gopsutil/disk"
+)
+
+func getLocalDiskHwOBD(ctx context.Context) madmin.ServerDiskHwOBDInfo {
+	addr := ""
+	if globalIsDistXL {
+		addr = GetLocalPeer(globalEndpoints)
+	} else {
+		addr = "minio"
+	}
+
+	partitions, err := diskhw.PartitionsWithContext(ctx, true)
+	if err != nil {
+		return madmin.ServerDiskHwOBDInfo{
+			Addr:  addr,
+			Error: err.Error(),
+		}
+	}
+
+	drives := []string{}
+	paths := []string{}
+	for _, partition := range partitions {
+		device := partition.Device
+		path := partition.Mountpoint
+		if strings.Index(device, "/dev/") == 0 {
+			if strings.Contains(device, "loop") {
+				continue
+			}
+			drives = append(drives, device)
+			paths = append(paths, path)
+		}
+	}
+
+	ioCounters, err := diskhw.IOCountersWithContext(ctx, drives...)
+	if err != nil {
+		return madmin.ServerDiskHwOBDInfo{
+			Addr:  addr,
+			Error: err.Error(),
+		}
+	}
+	usages := []*diskhw.UsageStat{}
+	for _, path := range paths {
+		usage, err := diskhw.UsageWithContext(ctx, path)
+		if err != nil {
+			return madmin.ServerDiskHwOBDInfo{
+				Addr:  addr,
+				Error: err.Error(),
+			}
+		}
+		usages = append(usages, usage)
+	}
+
+	return madmin.ServerDiskHwOBDInfo{
+		Addr:       addr,
+		Usage:      usages,
+		Partitions: partitions,
+		Counters:   ioCounters,
+		Error:      "",
+	}
+}