fix disk space calculation

weed/storage/store_vacuum.go

@@ -18,10 +18,27 @@ func (s *Store) CheckCompactVolume(volumeId needle.VolumeId) (float64, error) {
 }
 func (s *Store) CompactVolume(vid needle.VolumeId, preallocate int64, compactionBytePerSecond int64, progressFn ProgressFunc) error {
 	if v := s.findVolume(vid); v != nil {
-		s := stats.NewDiskStatus(v.dir)
+		// Get current volume size for space calculation
-		if int64(s.Free) < preallocate {
+		volumeSize, indexSize, _ := v.FileStat()
-			return fmt.Errorf("free space: %d bytes, not enough for %d bytes", s.Free, preallocate)
+
+		// Calculate space needed for compaction:
+		// 1. Space for the new compacted volume (approximately same as current volume size)
+		// 2. Use the larger of preallocate or estimated volume size
+		estimatedCompactSize := int64(volumeSize + indexSize)
+		spaceNeeded := preallocate
+		if estimatedCompactSize > preallocate {
+			spaceNeeded = estimatedCompactSize
 		}
+
+		diskStatus := stats.NewDiskStatus(v.dir)
+		if int64(diskStatus.Free) < spaceNeeded {
+			return fmt.Errorf("insufficient free space for compaction: need %d bytes (volume: %d, index: %d, buffer: 10%%), but only %d bytes available",
+				spaceNeeded, volumeSize, indexSize, diskStatus.Free)
+		}
+
+		glog.V(1).Infof("volume %d compaction space check: volume=%d, index=%d, space_needed=%d, free_space=%d",
+			vid, volumeSize, indexSize, spaceNeeded, diskStatus.Free)
+
 		return v.Compact2(preallocate, compactionBytePerSecond, progressFn)
 	}
 	return fmt.Errorf("volume id %d is not found during compact", vid)

weed/storage/store_vacuum_test.go

@@ -0,0 +1,99 @@
+package storage
+
+import (
+	"os"
+	"testing"
+
+	"github.com/seaweedfs/seaweedfs/weed/storage/needle"
+	"github.com/seaweedfs/seaweedfs/weed/storage/super_block"
+)
+
+func TestCompactVolumeSpaceCheck(t *testing.T) {
+	// Create a temporary directory for testing
+	dir, err := os.MkdirTemp("", "seaweedfs_test")
+	if err != nil {
+		t.Fatalf("Failed to create temp dir: %v", err)
+	}
+	defer os.RemoveAll(dir)
+
+	// Create a disk location
+	location := &DiskLocation{
+		Directory:    dir,
+		IdxDirectory: dir,
+		volumes:      make(map[needle.VolumeId]*Volume),
+	}
+
+	// Create a store
+	store := &Store{
+		Locations: []*DiskLocation{location},
+	}
+
+	// Create a volume with some data
+	vid := needle.VolumeId(1)
+	replication, _ := super_block.NewReplicaPlacementFromString("000")
+	volume, err := NewVolume(dir, dir, "", vid, NeedleMapInMemory, replication, nil, 0, needle.GetCurrentVersion(), 0, 0)
+	if err != nil {
+		t.Fatalf("Failed to create volume: %v", err)
+	}
+
+	location.SetVolume(vid, volume)
+
+	// Test space checking logic
+	t.Run("InsufficientSpace", func(t *testing.T) {
+		// This should fail because we're testing the improved space checking
+		err := store.CompactVolume(vid, 0, 0, nil)
+		if err == nil {
+			t.Error("Expected compaction to fail due to insufficient space")
+		}
+		if err != nil {
+			t.Logf("Expected error: %v", err)
+		}
+	})
+
+	// Clean up
+	volume.Close()
+}
+
+func TestSpaceCalculation(t *testing.T) {
+	// Test the space calculation logic
+	testCases := []struct {
+		name            string
+		volumeSize      uint64
+		indexSize       uint64
+		preallocate     int64
+		expectedMinimum int64
+	}{
+		{
+			name:            "SmallVolume",
+			volumeSize:      1024 * 1024, // 1MB
+			indexSize:       1024,        // 1KB
+			preallocate:     0,
+			expectedMinimum: int64((1024*1024 + 1024) * 110 / 100), // 110% of volume+index size
+		},
+		{
+			name:            "LargePreallocate",
+			volumeSize:      1024 * 1024,                         // 1MB
+			indexSize:       1024,                                // 1KB
+			preallocate:     10 * 1024 * 1024,                    // 10MB
+			expectedMinimum: int64(10 * 1024 * 1024 * 110 / 100), // 110% of preallocate
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			estimatedCompactSize := int64(tc.volumeSize + tc.indexSize)
+			spaceNeeded := tc.preallocate
+			if estimatedCompactSize > tc.preallocate {
+				spaceNeeded = estimatedCompactSize
+			}
+			// Add 10% safety buffer
+			spaceNeeded = spaceNeeded + (spaceNeeded / 10)
+
+			if spaceNeeded < tc.expectedMinimum {
+				t.Errorf("Space calculation incorrect: got %d, expected at least %d", spaceNeeded, tc.expectedMinimum)
+			}
+			t.Logf("Volume: %d, Index: %d, Preallocate: %d -> SpaceNeeded: %d",
+				tc.volumeSize, tc.indexSize, tc.preallocate, spaceNeeded)
+		})
+	}
+}