fix hard coded erasure_coding values

weed/storage/erasure_coding/ec_encoder.go

@@ -18,6 +18,7 @@ const (
 	DataShardsCount             = 10
 	ParityShardsCount           = 4
 	TotalShardsCount            = DataShardsCount + ParityShardsCount
+	MinTotalDisks               = TotalShardsCount/ParityShardsCount + 1
 	ErasureCodingLargeBlockSize = 1024 * 1024 * 1024 // 1GB
 	ErasureCodingSmallBlockSize = 1024 * 1024        // 1MB
 )

weed/worker/tasks/erasure_coding/detection.go

@@ -173,13 +173,10 @@ func planECDestinations(activeTopology *topology.ActiveTopology, metric *types.V
 		}
 	}
 
-	// Determine minimum shard disk locations based on configuration
-	minTotalDisks := 4
-
 	// Get available disks for EC placement (include source node for EC)
 	availableDisks := activeTopology.GetAvailableDisks(topology.TaskTypeErasureCoding, "")
-	if len(availableDisks) < minTotalDisks {
-		return nil, fmt.Errorf("insufficient disks for EC placement: need %d, have %d", minTotalDisks, len(availableDisks))
+	if len(availableDisks) < erasure_coding.MinTotalDisks {
+		return nil, fmt.Errorf("insufficient disks for EC placement: need %d, have %d", erasure_coding.MinTotalDisks, len(availableDisks))
 	}
 
 	// Select best disks for EC placement with rack/DC diversity