Reject illegal initial_scan_rate_limit value(less than 1024) (#16485)

close #16488

Signed-off-by: RidRisR <79858083+RidRisR@users.noreply.github.com>

Co-authored-by: ti-chi-bot[bot] <108142056+ti-chi-bot[bot]@users.noreply.github.com>

src/config/mod.rs

@@ -2910,6 +2910,9 @@ impl BackupStreamConfig {
         if self.initial_scan_concurrency == 0 {
             return Err("the `initial_scan_concurrency` shouldn't be zero".into());
         }
+        if self.initial_scan_rate_limit.0 < 1024 {
+            return Err("the `initial_scan_rate_limit` should be at least 1024 bytes".into());
+        }
         Ok(())
     }
 }
@@ -5336,6 +5339,19 @@ mod tests {
         tikv_cfg.validate().unwrap();
     }
 
+    #[test]
+    fn test_illegal_backupstream_config_parm() {
+        let mut backup_stream_cfg = BackupStreamConfig::default();
+        backup_stream_cfg.initial_scan_rate_limit.0 = 0;
+        backup_stream_cfg.validate().unwrap_err();
+        backup_stream_cfg.initial_scan_rate_limit.0 = 1000;
+        backup_stream_cfg.validate().unwrap_err();
+        backup_stream_cfg.initial_scan_rate_limit.0 = 1024;
+        backup_stream_cfg.validate().unwrap();
+        backup_stream_cfg.initial_scan_rate_limit.0 = 2048;
+        backup_stream_cfg.validate().unwrap();
+    }
+
     #[test]
     fn test_block_size() {
         let mut tikv_cfg = TikvConfig::default();