Read drive IO stats from sysfs instead of procfs (#19131)

Currently, we read from `/proc/diskstats` which is found to be un-reliable in k8s environments. We can read from `sysfs` instead. Also, cache the latest drive io stats to find the diff and update the metrics.
2026-07-22 21:50:22 +03:00 · 2024-02-27 01:04:50 +05:30
parent 2b5e4b853c
commit 30c2596512
13 changed files with 243 additions and 192 deletions
@@ -0,0 +1,130 @@
+//go:build linux && !s390x && !arm && !386
+// +build linux,!s390x,!arm,!386
+
+// Copyright (c) 2015-2024 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package disk
+
+import (
+	"os"
+	"reflect"
+	"runtime"
+	"testing"
+)
+
+func TestReadDriveStats(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("skipping this test in windows")
+	}
+	testCases := []struct {
+		stat            string
+		expectedIOStats IOStats
+		expectErr       bool
+	}{
+		{
+			stat: "1432553   420084 66247626  2398227  7077314  8720147 157049224  7469810        0  7580552  9869354    46037        0 41695120     1315        0        0",
+			expectedIOStats: IOStats{
+				ReadIOs:        1432553,
+				ReadMerges:     420084,
+				ReadSectors:    66247626,
+				ReadTicks:      2398227,
+				WriteIOs:       7077314,
+				WriteMerges:    8720147,
+				WriteSectors:   157049224,
+				WriteTicks:     7469810,
+				CurrentIOs:     0,
+				TotalTicks:     7580552,
+				ReqTicks:       9869354,
+				DiscardIOs:     46037,
+				DiscardMerges:  0,
+				DiscardSectors: 41695120,
+				DiscardTicks:   1315,
+				FlushIOs:       0,
+				FlushTicks:     0,
+			},
+			expectErr: false,
+		},
+		{
+			stat: "1432553   420084 66247626  2398227  7077314  8720147 157049224  7469810        0  7580552  9869354    46037        0 41695120     1315",
+			expectedIOStats: IOStats{
+				ReadIOs:        1432553,
+				ReadMerges:     420084,
+				ReadSectors:    66247626,
+				ReadTicks:      2398227,
+				WriteIOs:       7077314,
+				WriteMerges:    8720147,
+				WriteSectors:   157049224,
+				WriteTicks:     7469810,
+				CurrentIOs:     0,
+				TotalTicks:     7580552,
+				ReqTicks:       9869354,
+				DiscardIOs:     46037,
+				DiscardMerges:  0,
+				DiscardSectors: 41695120,
+				DiscardTicks:   1315,
+			},
+			expectErr: false,
+		},
+		{
+			stat: "1432553   420084 66247626  2398227  7077314  8720147 157049224  7469810        0  7580552  9869354",
+			expectedIOStats: IOStats{
+				ReadIOs:      1432553,
+				ReadMerges:   420084,
+				ReadSectors:  66247626,
+				ReadTicks:    2398227,
+				WriteIOs:     7077314,
+				WriteMerges:  8720147,
+				WriteSectors: 157049224,
+				WriteTicks:   7469810,
+				CurrentIOs:   0,
+				TotalTicks:   7580552,
+				ReqTicks:     9869354,
+			},
+			expectErr: false,
+		},
+		{
+			stat:            "1432553   420084 66247626  2398227",
+			expectedIOStats: IOStats{},
+			expectErr:       true,
+		},
+	}
+
+	for _, testCase := range testCases {
+		testCase := testCase
+		t.Run("", func(t *testing.T) {
+			tmpfile, err := os.CreateTemp("", "testfile")
+			if err != nil {
+				t.Error(err)
+			}
+			tmpfile.WriteString(testCase.stat)
+			tmpfile.Sync()
+			tmpfile.Close()
+
+			iostats, err := readDriveStats(tmpfile.Name())
+			if err != nil && !testCase.expectErr {
+				t.Fatalf("unexpected err; %v", err)
+			}
+			if testCase.expectErr && err == nil {
+				t.Fatal("expected to fail but err is nil")
+			}
+			if !reflect.DeepEqual(iostats, testCase.expectedIOStats) {
+				t.Fatalf("expected iostats: %v but got %v", testCase.expectedIOStats, iostats)
+			}
+		})
+	}
+}