[pbs-devel] [RFC v2 proxmox-backup 42/42] api: backup: add no-cache flag to bypass local datastore cache

Christian Ebner c.ebner at proxmox.com
Thu May 29 16:32:07 CEST 2025


Adds the `no-cache` flag so the client can request to bypass the
local datastore cache for chunk uploads. This is mainly intended for
debugging and benchmarking, but can be used in cases the caching is
known to be ineffective (no possible deduplication).

Signed-off-by: Christian Ebner <c.ebner at proxmox.com>
---
 examples/upload-speed.rs               |  1 +
 pbs-client/src/backup_writer.rs        |  4 +++-
 proxmox-backup-client/src/benchmark.rs |  1 +
 proxmox-backup-client/src/main.rs      |  8 ++++++++
 src/api2/backup/environment.rs         |  3 +++
 src/api2/backup/mod.rs                 |  3 +++
 src/api2/backup/upload_chunk.rs        | 11 +++++++++++
 src/server/push.rs                     |  1 +
 8 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/examples/upload-speed.rs b/examples/upload-speed.rs
index e4b570ec5..8a6594a47 100644
--- a/examples/upload-speed.rs
+++ b/examples/upload-speed.rs
@@ -25,6 +25,7 @@ async fn upload_speed() -> Result<f64, Error> {
         &(BackupType::Host, "speedtest".to_string(), backup_time).into(),
         false,
         true,
+        false,
     )
     .await?;
 
diff --git a/pbs-client/src/backup_writer.rs b/pbs-client/src/backup_writer.rs
index 325425069..a91880720 100644
--- a/pbs-client/src/backup_writer.rs
+++ b/pbs-client/src/backup_writer.rs
@@ -82,6 +82,7 @@ impl BackupWriter {
         backup: &BackupDir,
         debug: bool,
         benchmark: bool,
+        no_cache: bool,
     ) -> Result<Arc<BackupWriter>, Error> {
         let mut param = json!({
             "backup-type": backup.ty(),
@@ -89,7 +90,8 @@ impl BackupWriter {
             "backup-time": backup.time,
             "store": datastore,
             "debug": debug,
-            "benchmark": benchmark
+            "benchmark": benchmark,
+            "no-cache": no_cache,
         });
 
         if !ns.is_root() {
diff --git a/proxmox-backup-client/src/benchmark.rs b/proxmox-backup-client/src/benchmark.rs
index a6f24d745..ed21c7a91 100644
--- a/proxmox-backup-client/src/benchmark.rs
+++ b/proxmox-backup-client/src/benchmark.rs
@@ -236,6 +236,7 @@ async fn test_upload_speed(
         &(BackupType::Host, "benchmark".to_string(), backup_time).into(),
         false,
         true,
+        true,
     )
     .await?;
 
diff --git a/proxmox-backup-client/src/main.rs b/proxmox-backup-client/src/main.rs
index 44f4f5db5..83fc9309a 100644
--- a/proxmox-backup-client/src/main.rs
+++ b/proxmox-backup-client/src/main.rs
@@ -742,6 +742,12 @@ fn spawn_catalog_upload(
                 optional: true,
                 default: false,
             },
+            "no-cache": {
+                type: Boolean,
+                description: "Bypass local datastore cache for network storages.",
+                optional: true,
+                default: false,
+            },
         }
     }
  )]
@@ -754,6 +760,7 @@ async fn create_backup(
     change_detection_mode: Option<BackupDetectionMode>,
     dry_run: bool,
     skip_e2big_xattr: bool,
+    no_cache: bool,
     limit: ClientRateLimitConfig,
     _info: &ApiMethod,
     _rpcenv: &mut dyn RpcEnvironment,
@@ -960,6 +967,7 @@ async fn create_backup(
         &snapshot,
         true,
         false,
+        no_cache,
     )
     .await?;
 
diff --git a/src/api2/backup/environment.rs b/src/api2/backup/environment.rs
index 384e8a73f..874f0c44d 100644
--- a/src/api2/backup/environment.rs
+++ b/src/api2/backup/environment.rs
@@ -112,6 +112,7 @@ pub struct BackupEnvironment {
     result_attributes: Value,
     auth_id: Authid,
     pub debug: bool,
+    pub no_cache: bool,
     pub formatter: &'static dyn OutputFormatter,
     pub worker: Arc<WorkerTask>,
     pub datastore: Arc<DataStore>,
@@ -128,6 +129,7 @@ impl BackupEnvironment {
         worker: Arc<WorkerTask>,
         datastore: Arc<DataStore>,
         backup_dir: BackupDir,
+        no_cache: bool,
     ) -> Result<Self, Error> {
         let state = SharedBackupState {
             finished: false,
@@ -148,6 +150,7 @@ impl BackupEnvironment {
             worker,
             datastore,
             debug: tracing::enabled!(tracing::Level::DEBUG),
+            no_cache,
             formatter: JSON_FORMATTER,
             backup_dir,
             last_backup: None,
diff --git a/src/api2/backup/mod.rs b/src/api2/backup/mod.rs
index 2c6afca41..0913d4264 100644
--- a/src/api2/backup/mod.rs
+++ b/src/api2/backup/mod.rs
@@ -51,6 +51,7 @@ pub const API_METHOD_UPGRADE_BACKUP: ApiMethod = ApiMethod::new(
             ("backup-time", false, &BACKUP_TIME_SCHEMA),
             ("debug", true, &BooleanSchema::new("Enable verbose debug logging.").schema()),
             ("benchmark", true, &BooleanSchema::new("Job is a benchmark (do not keep data).").schema()),
+            ("no-cache", true, &BooleanSchema::new("Disable local datastore cache for network storages").schema()),
         ]),
     )
 ).access(
@@ -77,6 +78,7 @@ fn upgrade_to_backup_protocol(
     async move {
         let debug = param["debug"].as_bool().unwrap_or(false);
         let benchmark = param["benchmark"].as_bool().unwrap_or(false);
+        let no_cache = param["no-cache"].as_bool().unwrap_or(false);
 
         let auth_id: Authid = rpcenv.get_auth_id().unwrap().parse()?;
 
@@ -212,6 +214,7 @@ fn upgrade_to_backup_protocol(
                     worker.clone(),
                     datastore,
                     backup_dir,
+                    no_cache,
                 )?;
 
                 env.debug = debug;
diff --git a/src/api2/backup/upload_chunk.rs b/src/api2/backup/upload_chunk.rs
index 7a80fd0eb..4e949a073 100644
--- a/src/api2/backup/upload_chunk.rs
+++ b/src/api2/backup/upload_chunk.rs
@@ -247,6 +247,17 @@ async fn upload_to_backend(
             UploadChunk::new(req_body, env.datastore.clone(), digest, size, encoded_size).await
         }
         DatastoreBackend::S3(s3_client) => {
+            if env.no_cache {
+                let is_duplicate = match s3_client.put_object(digest.into(), req_body).await? {
+                    PutObjectResponse::PreconditionFailed => true,
+                    PutObjectResponse::NeedsRetry => {
+                        bail!("concurrent operation, reupload required")
+                    }
+                    PutObjectResponse::Success(_content) => false,
+                };
+                return Ok((digest, size, encoded_size, is_duplicate));
+            }
+
             // Load chunk data into memory, need to write it twice, to S3 object store and
             // local cache store. Further, body needs to be consumed also if chunks insert
             // can be skipped since cached.
diff --git a/src/server/push.rs b/src/server/push.rs
index e71012ed8..6a31d2abe 100644
--- a/src/server/push.rs
+++ b/src/server/push.rs
@@ -828,6 +828,7 @@ pub(crate) async fn push_snapshot(
         snapshot,
         false,
         false,
+        false,
     )
     .await?;
 
-- 
2.39.5





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