diff --git a/internal/piecewriter/piecewriter.go b/internal/piecewriter/piecewriter.go
index d6908c69..d2a37bdb 100644
--- a/internal/piecewriter/piecewriter.go
+++ b/internal/piecewriter/piecewriter.go
@@ -5,6 +5,7 @@ import (
 
 	"github.com/cenkalti/rain/internal/bufferpool"
 	"github.com/cenkalti/rain/internal/piece"
+	"github.com/cenkalti/rain/internal/semaphore"
 	"github.com/rcrowley/go-metrics"
 )
 
@@ -25,12 +26,14 @@ func New(p *piece.Piece, source interface{}, buf bufferpool.Buffer) *PieceWriter
 	}
 }
 
-func (w *PieceWriter) Run(resultC chan *PieceWriter, closeC chan struct{}, writesPerSecond, writeBytesPerSecond metrics.EWMA) {
+func (w *PieceWriter) Run(resultC chan *PieceWriter, closeC chan struct{}, writesPerSecond, writeBytesPerSecond metrics.EWMA, sem *semaphore.Semaphore) {
 	w.HashOK = w.Piece.VerifyHash(w.Buffer.Data, sha1.New()) // nolint: gosec
 	if w.HashOK {
 		writesPerSecond.Update(1)
 		writeBytesPerSecond.Update(int64(len(w.Buffer.Data)))
+		sem.Wait()
 		_, w.Error = w.Piece.Data.Write(w.Buffer.Data)
+		sem.Signal()
 	}
 	select {
 	case resultC <- w:
diff --git a/internal/rpctypes/rpctypes.go b/internal/rpctypes/rpctypes.go
index e1a23b0c..2bbb1d08 100644
--- a/internal/rpctypes/rpctypes.go
+++ b/internal/rpctypes/rpctypes.go
@@ -63,6 +63,8 @@ type SessionStats struct {
 	Uptime                        int
 	WritesPerSecond               int
 	WriteBytesPerSecond           int
+	WritesActive                  int
+	WritesPending                 int
 }
 
 type Stats struct {
diff --git a/torrent/config.go b/torrent/config.go
index 6940658b..3ec4b47b 100644
--- a/torrent/config.go
+++ b/torrent/config.go
@@ -128,6 +128,8 @@ type Config struct {
 	PieceCacheTTL time.Duration
 	// Number of read operations to do in parallel.
 	ParallelReads uint
+	// Number of write operations to do in parallel.
+	ParallelWrites uint
 
 	// When the client want to connect a peer, first it tries to do encrypted handshake.
 	// If it does not work, it connects to same peer again and does unencrypted handshake.
@@ -223,6 +225,7 @@ var DefaultConfig = Config{
 	PieceCacheSize: 256 * 1024 * 1024,
 	PieceCacheTTL:  5 * time.Minute,
 	ParallelReads:  1,
+	ParallelWrites: 1,
 
 	// Webseed settings
 	WebseedDialTimeout:             10 * time.Second,
diff --git a/torrent/session.go b/torrent/session.go
index 31771c62..003f173b 100644
--- a/torrent/session.go
+++ b/torrent/session.go
@@ -21,6 +21,7 @@ import (
 	"github.com/cenkalti/rain/internal/resolver"
 	"github.com/cenkalti/rain/internal/resourcemanager"
 	"github.com/cenkalti/rain/internal/resumer/boltdbresumer"
+	"github.com/cenkalti/rain/internal/semaphore"
 	"github.com/cenkalti/rain/internal/storage/filestorage"
 	"github.com/cenkalti/rain/internal/tracker"
 	"github.com/cenkalti/rain/internal/trackermanager"
@@ -68,6 +69,7 @@ type Session struct {
 
 	writesPerSecond     metrics.EWMA
 	writeBytesPerSecond metrics.EWMA
+	semWrite            *semaphore.Semaphore
 }
 
 // NewSession creates a new Session for downloading and seeding torrents.
@@ -183,6 +185,7 @@ func NewSession(cfg Config) (*Session, error) {
 		},
 		writesPerSecond:     metrics.NewEWMA1(),
 		writeBytesPerSecond: metrics.NewEWMA1(),
+		semWrite:            semaphore.New(int(cfg.ParallelWrites)),
 	}
 	ext, err := bitfield.NewBytes(c.extensions[:], 64)
 	if err != nil {
diff --git a/torrent/session_rpc_handler.go b/torrent/session_rpc_handler.go
index 4ffade58..40a511cf 100644
--- a/torrent/session_rpc_handler.go
+++ b/torrent/session_rpc_handler.go
@@ -94,6 +94,8 @@ func (h *rpcHandler) GetSessionStats(args *rpctypes.GetSessionStatsRequest, repl
 		Uptime:                        int(s.Uptime / time.Second),
 		WritesPerSecond:               s.WritesPerSecond,
 		WriteBytesPerSecond:           s.WriteBytesPerSecond,
+		WritesActive:                  s.WritesActive,
+		WritesPending:                 s.WritesPending,
 	}
 	return nil
 }
diff --git a/torrent/session_stats.go b/torrent/session_stats.go
index 673489b7..0b259e7f 100644
--- a/torrent/session_stats.go
+++ b/torrent/session_stats.go
@@ -26,6 +26,8 @@ type SessionStats struct {
 	Uptime                        time.Duration
 	WritesPerSecond               int
 	WriteBytesPerSecond           int
+	WritesActive                  int
+	WritesPending                 int
 }
 
 func (s *Session) Stats() SessionStats {
@@ -60,6 +62,8 @@ func (s *Session) Stats() SessionStats {
 		Uptime:                        time.Since(s.createdAt),
 		WritesPerSecond:               int(s.writesPerSecond.Rate()),
 		WriteBytesPerSecond:           int(s.writeBytesPerSecond.Rate()),
+		WritesActive:                  s.semWrite.Len(),
+		WritesPending:                 s.semWrite.Waiting(),
 	}
 }
 
diff --git a/torrent/torrent_messagehandler.go b/torrent/torrent_messagehandler.go
index 4318b783..5c793e63 100644
--- a/torrent/torrent_messagehandler.go
+++ b/torrent/torrent_messagehandler.go
@@ -107,7 +107,7 @@ func (t *torrent) handlePieceMessage(pm peer.PieceMessage) {
 	t.webseedPieceResultC.Suspend()
 
 	pw := piecewriter.New(piece, pe, pd.Buffer)
-	go pw.Run(t.pieceWriterResultC, t.doneC, t.session.writesPerSecond, t.session.writeBytesPerSecond)
+	go pw.Run(t.pieceWriterResultC, t.doneC, t.session.writesPerSecond, t.session.writeBytesPerSecond, t.session.semWrite)
 }
 
 func (t *torrent) handlePeerMessage(pm peer.Message) {
diff --git a/torrent/torrent_webseed.go b/torrent/torrent_webseed.go
index c1386f75..7b59e603 100644
--- a/torrent/torrent_webseed.go
+++ b/torrent/torrent_webseed.go
@@ -43,7 +43,7 @@ func (t *torrent) handleWebseedPieceResult(msg *urldownloader.PieceResult) {
 	t.webseedPieceResultC.Suspend()
 
 	pw := piecewriter.New(piece, msg.Downloader, msg.Buffer)
-	go pw.Run(t.pieceWriterResultC, t.doneC, t.session.writesPerSecond, t.session.writeBytesPerSecond)
+	go pw.Run(t.pieceWriterResultC, t.doneC, t.session.writesPerSecond, t.session.writeBytesPerSecond, t.session.semWrite)
 
 	if msg.Done {
 		for _, src := range t.webseedSources {