diff --git a/migration/block.c b/migration/block.c
index 5c03632257..03bbba61cb 100644
--- a/migration/block.c
+++ b/migration/block.c
@@ -37,6 +37,7 @@
 #define MAX_IS_ALLOCATED_SEARCH (65536 * BDRV_SECTOR_SIZE)
 
 #define MAX_IO_BUFFERS 512
+#define MAX_PARALLEL_IO 16
 
 //#define DEBUG_BLK_MIGRATION
 
@@ -775,6 +776,7 @@ static int block_save_iterate(QEMUFile *f, void *opaque)
     while ((block_mig_state.submitted +
             block_mig_state.read_done) * BLOCK_SIZE <
            qemu_file_get_rate_limit(f) &&
+           block_mig_state.submitted < MAX_PARALLEL_IO &&
            (block_mig_state.submitted + block_mig_state.read_done) <
            MAX_IO_BUFFERS) {
         blk_mig_unlock();