diff --git a/config.toml.example b/config.toml.example
index 0bc4dc46748d79c4f566735af827996aca24fc91..e056123a50b12ef8a5c1de10accda206210b661b 100644
--- a/config.toml.example
+++ b/config.toml.example
@@ -161,6 +161,9 @@ self_signed_cert = false
 # # Optional: defaults to 1
 # # The number of goroutines performing write-ahead log backups.
 # wal_backup_worker_count = 1
+# # Optional: defaults to 5,242,880 bytes (5MiB). If 0, the driver will choose a reasonable default.
+# # The size of each part in a multipart upload to object storage.
+# buffer_size = 0
 
 # # Bundle-URI
 # [bundle_uri]
diff --git a/internal/backup/sink.go b/internal/backup/sink.go
index 557e8254d0e17ba9f44f000b66455dbc47646783..d0fafc3279c2d183412718d8afa46572c1838879 100644
--- a/internal/backup/sink.go
+++ b/internal/backup/sink.go
@@ -24,7 +24,7 @@ import (
 // The storage engine is chosen based on the provided uri.
 // It is the caller's responsibility to provide all required environment
 // variables in order to get properly initialized storage engine driver.
-func ResolveSink(ctx context.Context, uri string) (*Sink, error) {
+func ResolveSink(ctx context.Context, uri string, opts ...SinkOption) (*Sink, error) {
 	parsed, err := url.Parse(uri)
 	if err != nil {
 		return nil, err
@@ -36,23 +36,44 @@ func ResolveSink(ctx context.Context, uri string) (*Sink, error) {
 		// a full set of variations. Instead we trim it up to the service option only.
 		scheme = scheme[i+1:]
 	}
-
+	var sink *Sink
 	switch scheme {
 	case s3blob.Scheme, azureblob.Scheme, gcsblob.Scheme, memblob.Scheme:
-		return newSink(ctx, uri)
+		sink, err = newSink(ctx, uri)
 	case fileblob.Scheme, "":
 		// fileblob.OpenBucket requires a bare path without 'file://'.
-		return newFileblobSink(parsed.Path)
+		sink, err = newFileblobSink(parsed.Path)
 	default:
 		return nil, fmt.Errorf("unsupported sink URI scheme: %q", scheme)
 	}
+
+	if err != nil {
+		return nil, fmt.Errorf("failed to create object storage sink: %w", err)
+	}
+
+	for _, opt := range opts {
+		opt(sink)
+	}
+
+	return sink, nil
+}
+
+// WithBufferSize sets the buffer size for the sink.
+func WithBufferSize(size int) SinkOption {
+	return func(s *Sink) {
+		s.bufferSize = size
+	}
 }
 
 // Sink uses a storage engine that can be defined by the construction url on creation.
 type Sink struct {
-	bucket *blob.Bucket
+	bucket     *blob.Bucket
+	bufferSize int
 }
 
+// SinkOption is a function that configures a Sink.
+type SinkOption func(*Sink)
+
 // newSink returns initialized instance of Sink instance.
 func newSink(ctx context.Context, url string) (*Sink, error) {
 	bucket, err := blob.OpenBucket(ctx, url)
@@ -98,6 +119,7 @@ func (s Sink) Close() error {
 // bucket. It is the callers responsibility to Close the reader after usage.
 func (s Sink) GetWriter(ctx context.Context, relativePath string) (io.WriteCloser, error) {
 	writer, err := s.bucket.NewWriter(ctx, relativePath, &blob.WriterOptions{
+		BufferSize: s.bufferSize,
 		// 'no-store' - we don't want the backup to be cached as the content could be changed,
 		// so we always want a fresh and up to date data
 		// https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cache-Control#cacheability
diff --git a/internal/cli/gitaly/serve.go b/internal/cli/gitaly/serve.go
index 9c90110e74478b90636719888438b28ddffa5c87..11b25e6015384648bc475d23e9fa497c9656d263 100644
--- a/internal/cli/gitaly/serve.go
+++ b/internal/cli/gitaly/serve.go
@@ -536,7 +536,7 @@ func run(appCtx *cli.Context, cfg config.Cfg, logger log.Logger) error {
 	var backupLocator backup.Locator
 	if cfg.Backup.GoCloudURL != "" {
 		var err error
-		backupSink, err = backup.ResolveSink(ctx, cfg.Backup.GoCloudURL)
+		backupSink, err = backup.ResolveSink(ctx, cfg.Backup.GoCloudURL, backup.WithBufferSize(cfg.Backup.BufferSize))
 		if err != nil {
 			return fmt.Errorf("resolve backup sink: %w", err)
 		}
diff --git a/internal/gitaly/config/config.go b/internal/gitaly/config/config.go
index 8b775f39b892ecebe3ff76667df3815b56431f2d..89b040ebb2f21d6092e614febc4f897bec8d3cbf 100644
--- a/internal/gitaly/config/config.go
+++ b/internal/gitaly/config/config.go
@@ -608,6 +608,8 @@ type BackupConfig struct {
 	WALWorkerCount uint `json:"wal_backup_worker_count,omitempty" toml:"wal_backup_worker_count,omitempty"`
 	// Layout determines how backup files are located.
 	Layout string `json:"layout,omitempty" toml:"layout,omitempty"`
+	// BufferSize specifies the size of the buffer used when uploading backup parts to object storage.
+	BufferSize int `json:"buffer_size,omitempty" toml:"buffer_size,omitempty"`
 }
 
 // Validate runs validation on all fields and returns any errors found.