client: pxar: optionally split metadata and payload streams

... and attach the split payload writer variant to the pxar archive
creation. By this, metadata and payload data will create different
dynamic indexes, allowing to lookup and reuse payload chunks without
the additional overhead of the pxar archive's metadata.

For now this functionality remains disabled and will be enabled in a
later patch once the logic for reusing the payload chunks is in
place.

Signed-off-by: Christian Ebner <c.ebner@proxmox.com>

pbs-client/src/pxar_backup_stream.rs

@@ -42,21 +42,37 @@ impl PxarBackupStream {
         dir: Dir,
         catalog: Arc<Mutex<CatalogWriter<W>>>,
         options: crate::pxar::PxarCreateOptions,
-    ) -> Result<Self, Error> {
-        let (tx, rx) = std::sync::mpsc::sync_channel(10);
-
+        separate_payload_stream: bool,
+    ) -> Result<(Self, Option<Self>), Error> {
         let buffer_size = 256 * 1024;
 
+        let (tx, rx) = std::sync::mpsc::sync_channel(10);
+        let writer = TokioWriterAdapter::new(std::io::BufWriter::with_capacity(
+            buffer_size,
+            StdChannelWriter::new(tx),
+        ));
+        let writer = pxar::encoder::sync::StandardWriter::new(writer);
+
+        let (writer, payload_rx) = if separate_payload_stream {
+            let (tx, rx) = std::sync::mpsc::sync_channel(10);
+            let payload_writer = TokioWriterAdapter::new(std::io::BufWriter::with_capacity(
+                buffer_size,
+                StdChannelWriter::new(tx),
+            ));
+            (
+                pxar::PxarVariant::Split(
+                    writer,
+                    pxar::encoder::sync::StandardWriter::new(payload_writer),
+                ),
+                Some(rx),
+            )
+        } else {
+            (pxar::PxarVariant::Unified(writer), None)
+        };
+
         let error = Arc::new(Mutex::new(None));
         let error2 = Arc::clone(&error);
         let handler = async move {
-            let writer = TokioWriterAdapter::new(std::io::BufWriter::with_capacity(
-                buffer_size,
-                StdChannelWriter::new(tx),
-            ));
-
-            let writer =
-                pxar::PxarVariant::Unified(pxar::encoder::sync::StandardWriter::new(writer));
             if let Err(err) = crate::pxar::create_archive(
                 dir,
                 PxarWriters::new(writer, Some(catalog)),
@@ -78,21 +94,30 @@ impl PxarBackupStream {
         let future = Abortable::new(handler, registration);
         tokio::spawn(future);
 
-        Ok(Self {
+        let backup_stream = Self {
+            rx: Some(rx),
+            handle: Some(handle.clone()),
+            error: Arc::clone(&error),
+        };
+
+        let backup_payload_stream = payload_rx.map(|rx| Self {
             rx: Some(rx),
             handle: Some(handle),
             error,
-        })
+        });
+
+        Ok((backup_stream, backup_payload_stream))
     }
 
     pub fn open<W: Write + Send + 'static>(
         dirname: &Path,
         catalog: Arc<Mutex<CatalogWriter<W>>>,
         options: crate::pxar::PxarCreateOptions,
-    ) -> Result<Self, Error> {
+        separate_payload_stream: bool,
+    ) -> Result<(Self, Option<Self>), Error> {
         let dir = nix::dir::Dir::open(dirname, OFlag::O_DIRECTORY, Mode::empty())?;
 
-        Self::new(dir, catalog, options)
+        Self::new(dir, catalog, options, separate_payload_stream)
     }
 }
 

proxmox-backup-client/src/main.rs

@@ -187,18 +187,24 @@ async fn backup_directory<P: AsRef<Path>>(
     client: &BackupWriter,
     dir_path: P,
     archive_name: &str,
+    payload_target: Option<&str>,
     chunk_size: Option<usize>,
     catalog: Arc<Mutex<CatalogWriter<TokioWriterAdapter<StdChannelWriter<Error>>>>>,
     pxar_create_options: pbs_client::pxar::PxarCreateOptions,
     upload_options: UploadOptions,
-) -> Result<BackupStats, Error> {
+) -> Result<(BackupStats, Option<BackupStats>), Error> {
     if upload_options.fixed_size.is_some() {
         bail!("cannot backup directory with fixed chunk size!");
     }
 
-    let pxar_stream = PxarBackupStream::open(dir_path.as_ref(), catalog, pxar_create_options)?;
-    let mut chunk_stream = ChunkStream::new(pxar_stream, chunk_size);
+    let (pxar_stream, payload_stream) = PxarBackupStream::open(
+        dir_path.as_ref(),
+        catalog,
+        pxar_create_options,
+        payload_target.is_some(),
+    )?;
 
+    let mut chunk_stream = ChunkStream::new(pxar_stream, chunk_size);
     let (tx, rx) = mpsc::channel(10); // allow to buffer 10 chunks
 
     let stream = ReceiverStream::new(rx).map_err(Error::from);
@@ -210,11 +216,36 @@ async fn backup_directory<P: AsRef<Path>>(
         }
     });
 
-    let stats = client
-        .upload_stream(archive_name, stream, upload_options)
-        .await?;
+    let stats = client.upload_stream(archive_name, stream, upload_options.clone());
 
-    Ok(stats)
+    if let Some(payload_stream) = payload_stream {
+        let payload_target = payload_target
+            .ok_or_else(|| format_err!("got payload stream, but no target archive name"))?;
+
+        let mut payload_chunk_stream = ChunkStream::new(payload_stream, chunk_size);
+        let (payload_tx, payload_rx) = mpsc::channel(10); // allow to buffer 10 chunks
+        let stream = ReceiverStream::new(payload_rx).map_err(Error::from);
+
+        // spawn payload chunker inside a separate task so that it can run parallel
+        tokio::spawn(async move {
+            while let Some(v) = payload_chunk_stream.next().await {
+                let _ = payload_tx.send(v).await;
+            }
+        });
+
+        let payload_stats = client.upload_stream(&payload_target, stream, upload_options);
+
+        match futures::join!(stats, payload_stats) {
+            (Ok(stats), Ok(payload_stats)) => Ok((stats, Some(payload_stats))),
+            (Err(err), Ok(_)) => Err(format_err!("upload failed: {err}")),
+            (Ok(_), Err(err)) => Err(format_err!("upload failed: {err}")),
+            (Err(err), Err(payload_err)) => {
+                Err(format_err!("upload failed: {err} - {payload_err}"))
+            }
+        }
+    } else {
+        Ok((stats.await?, None))
+    }
 }
 
 async fn backup_image<P: AsRef<Path>>(
@@ -985,6 +1016,23 @@ async fn create_backup(
                 manifest.add_file(target, stats.size, stats.csum, crypto.mode)?;
             }
             (BackupSpecificationType::PXAR, false) => {
+                let metadata_mode = false; // Until enabled via param
+
+                let target_base = if let Some(base) = target_base.strip_suffix(".pxar") {
+                    base.to_string()
+                } else {
+                    bail!("unexpected suffix in target: {target_base}");
+                };
+
+                let (target, payload_target) = if metadata_mode {
+                    (
+                        format!("{target_base}.mpxar.{extension}"),
+                        Some(format!("{target_base}.ppxar.{extension}")),
+                    )
+                } else {
+                    (target, None)
+                };
+
                 // start catalog upload on first use
                 if catalog.is_none() {
                     let catalog_upload_res =
@@ -1015,16 +1063,27 @@ async fn create_backup(
                     ..UploadOptions::default()
                 };
 
-                let stats = backup_directory(
+                let (stats, payload_stats) = backup_directory(
                     &client,
                     &filename,
                     &target,
+                    payload_target.as_deref(),
                     chunk_size_opt,
                     catalog.clone(),
                     pxar_options,
                     upload_options,
                 )
                 .await?;
+
+                if let Some(payload_stats) = payload_stats {
+                    manifest.add_file(
+                        payload_target
+                            .ok_or_else(|| format_err!("missing payload target archive"))?,
+                        payload_stats.size,
+                        payload_stats.csum,
+                        crypto.mode,
+                    )?;
+                }
                 manifest.add_file(target, stats.size, stats.csum, crypto.mode)?;
                 catalog.lock().unwrap().end_directory()?;
             }