diff --git a/src/data.c b/src/data.c
index f9c83e5d..2e1d034a 100644
--- a/src/data.c
+++ b/src/data.c
@@ -623,7 +623,7 @@ backup_data_file(ConnectionArgs* conn_arg, pgFile *file,
 	}
 
 	if (!fio_is_remote_file(in))
-		setbuffer(in, in_buffer, STDIO_BUFSIZE);
+		setvbuf(in, in_buffer, _IOFBF, STDIO_BUFSIZE);
 
 	/* open backup file for write  */
 	out = fopen(to_fullpath, PG_BINARY_W);
@@ -631,7 +631,7 @@ backup_data_file(ConnectionArgs* conn_arg, pgFile *file,
 		elog(ERROR, "Cannot open backup file \"%s\": %s",
 			 to_fullpath, strerror(errno));
 
-	setbuffer(out, out_buffer, STDIO_BUFSIZE);
+	setvbuf(out, out_buffer, _IOFBF, STDIO_BUFSIZE);
 
 	/* update file permission */
 	if (chmod(to_fullpath, FILE_PERMISSION) == -1)
@@ -874,7 +874,7 @@ restore_data_file(parray *parent_chain, pgFile *dest_file, FILE *out, const char
 			elog(ERROR, "Cannot open backup file \"%s\": %s", from_fullpath,
 				 strerror(errno));
 
-		setbuffer(in, buffer, STDIO_BUFSIZE);
+		setvbuf(in, buffer, _IOFBF, STDIO_BUFSIZE);
 
 		/*
 		 * Restore the file.
@@ -1164,7 +1164,7 @@ restore_non_data_file(parray *parent_chain, pgBackup *dest_backup,
 		elog(ERROR, "Cannot open backup file \"%s\": %s", from_fullpath,
 			 strerror(errno));
 
-	setbuffer(in, buffer, STDIO_BUFSIZE);
+	setvbuf(in, buffer, _IOFBF, STDIO_BUFSIZE);
 
 	/* do actual work */
 	restore_non_data_file_internal(in, out, tmp_file, from_fullpath, to_fullpath);
diff --git a/src/merge.c b/src/merge.c
index 295d4230..06da8f4b 100644
--- a/src/merge.c
+++ b/src/merge.c
@@ -1132,7 +1132,7 @@ merge_data_file(parray *parent_chain, pgBackup *full_backup,
 	if (out == NULL)
 		elog(ERROR, "Cannot open merge target file \"%s\": %s",
 			 to_fullpath_tmp1, strerror(errno));
-	setbuffer(out, buffer, STDIO_BUFSIZE);
+	setvbuf(out, buffer, _IOFBF, STDIO_BUFSIZE);
 
 	/* restore file into temp file */
 	tmp_file->size = restore_data_file(parent_chain, dest_file, out, to_fullpath_tmp1);
diff --git a/src/restore.c b/src/restore.c
index 4bd62e09..177f9d5f 100644
--- a/src/restore.c
+++ b/src/restore.c
@@ -857,7 +857,7 @@ restore_files(void *arg)
 			goto done;
 
 		if (!fio_is_remote_file(out))
-			setbuffer(out, buffer, STDIO_BUFSIZE);
+			setvbuf(out, buffer, _IOFBF, STDIO_BUFSIZE);
 
 		/* Restore destination file */
 		if (dest_file->is_datafile && !dest_file->is_cfs)