disabling of periodic snapshots with the --no-periodic-snapshot flag

parity/cli.rs

@@ -243,6 +243,8 @@ Snapshot Options:
                            index, hash, or 'latest'. Note that taking snapshots at
                            non-recent blocks will only work with --pruning archive
                            [default: latest]
+  --no-periodic-snapshot   Disable automated snapshots which usually occur once
+                           every 10000 blocks.
 
 Virtual Machine Options:
   --jitvm                  Enable the JIT VM.
@@ -382,6 +384,7 @@ pub struct Args {
 	pub flag_from: String,
 	pub flag_to: String,
 	pub flag_at: String,
+  pub flag_no_periodic_snapshot: bool,
 	pub flag_format: Option<String>,
 	pub flag_jitvm: bool,
 	pub flag_log_file: Option<String>,

parity/configuration.rs

@@ -226,6 +226,7 @@ impl Configuration {
 				ui: self.args.cmd_ui,
 				name: self.args.flag_identity,
 				custom_bootnodes: self.args.flag_bootnodes.is_some(),
+				no_periodic_snapshot: self.args.flag_no_periodic_snapshot,
 			};
 			Cmd::Run(run_cmd)
 		};
@@ -802,6 +803,7 @@ mod tests {
 			ui: false,
 			name: "".into(),
 			custom_bootnodes: false,
+			no_periodic_snapshot: false,
 		}));
 	}
 

parity/run.rs

@@ -47,7 +47,10 @@ use rpc_apis;
 use rpc;
 use url;
 
+// how often to take periodic snapshots.
 const SNAPSHOT_PERIOD: u64 = 10000;
+
+// how many blocks to wait before starting a periodic snapshot.
 const SNAPSHOT_HISTORY: u64 = 1000;
 
 #[derive(Debug, PartialEq)]
@@ -81,6 +84,7 @@ pub struct RunCmd {
 	pub ui: bool,
 	pub name: String,
 	pub custom_bootnodes: bool,
+	pub no_periodic_snapshot: bool,
 }
 
 pub fn execute(cmd: RunCmd) -> Result<(), String> {
@@ -253,14 +257,16 @@ pub fn execute(cmd: RunCmd) -> Result<(), String> {
 	});
 	service.register_io_handler(io_handler).expect("Error registering IO handler");
 
-	let watcher = snapshot::Watcher::new(
-		service.client(),
-		service.io().channel(),
-		SNAPSHOT_PERIOD,
-		SNAPSHOT_HISTORY,
-	);
+	if !cmd.no_periodic_snapshot {
+		let watcher = snapshot::Watcher::new(
+			service.client(),
+			service.io().channel(),
+			SNAPSHOT_PERIOD,
+			SNAPSHOT_HISTORY,
+		);
 
-	service.add_notify(Arc::new(watcher));
+		service.add_notify(Arc::new(watcher));
+	}
 
 	// start ui
 	if cmd.ui {