1 files changed, 82 insertions, 0 deletions
diff --git a/weed/worker/tasks/balance/balance.go b/weed/worker/tasks/balance/balance.go
new file mode 100644
index 000000000..ea867d950
--- /dev/null
+++ b/weed/worker/tasks/balance/balance.go
@@ -0,0 +1,82 @@
+package balance
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/seaweedfs/seaweedfs/weed/glog"
+	"github.com/seaweedfs/seaweedfs/weed/worker/tasks"
+	"github.com/seaweedfs/seaweedfs/weed/worker/types"
+)
+
+// Task implements balance operation to redistribute volumes across volume servers
+type Task struct {
+	*tasks.BaseTask
+	server     string
+	volumeID   uint32
+	collection string
+}
+
+// NewTask creates a new balance task instance
+func NewTask(server string, volumeID uint32, collection string) *Task {
+	task := &Task{
+		BaseTask:   tasks.NewBaseTask(types.TaskTypeBalance),
+		server:     server,
+		volumeID:   volumeID,
+		collection: collection,
+	}
+	return task
+}
+
+// Execute executes the balance task
+func (t *Task) Execute(params types.TaskParams) error {
+	glog.Infof("Starting balance task for volume %d on server %s (collection: %s)", t.volumeID, t.server, t.collection)
+
+	// Simulate balance operation with progress updates
+	steps := []struct {
+		name     string
+		duration time.Duration
+		progress float64
+	}{
+		{"Analyzing cluster state", 2 * time.Second, 15},
+		{"Identifying optimal placement", 3 * time.Second, 35},
+		{"Moving volume data", 6 * time.Second, 75},
+		{"Updating cluster metadata", 2 * time.Second, 95},
+		{"Verifying balance", 1 * time.Second, 100},
+	}
+
+	for _, step := range steps {
+		if t.IsCancelled() {
+			return fmt.Errorf("balance task cancelled")
+		}
+
+		glog.V(1).Infof("Balance task step: %s", step.name)
+		t.SetProgress(step.progress)
+
+		// Simulate work
+		time.Sleep(step.duration)
+	}
+
+	glog.Infof("Balance task completed for volume %d on server %s", t.volumeID, t.server)
+	return nil
+}
+
+// Validate validates the task parameters
+func (t *Task) Validate(params types.TaskParams) error {
+	if params.VolumeID == 0 {
+		return fmt.Errorf("volume_id is required")
+	}
+	if params.Server == "" {
+		return fmt.Errorf("server is required")
+	}
+	return nil
+}
+
+// EstimateTime estimates the time needed for the task
+func (t *Task) EstimateTime(params types.TaskParams) time.Duration {
+	// Base time for balance operation
+	baseTime := 35 * time.Second
+
+	// Could adjust based on volume size or cluster state
+	return baseTime
+}