# SeaweedFS RDMA Sidecar - Future Work TODO

## 🎯 **Current Status (✅ COMPLETED)**

### **Phase 1: Architecture & Integration - DONE**
- ✅ **Complete Go ↔ Rust IPC Pipeline**: Unix sockets + MessagePack
- ✅ **SeaweedFS Integration**: Mount client with RDMA acceleration
- ✅ **Docker Orchestration**: Multi-service setup with proper networking
- ✅ **Error Handling**: Robust fallback and recovery mechanisms
- ✅ **Performance Optimizations**: Zero-copy page cache + connection pooling
- ✅ **Code Quality**: All GitHub PR review comments addressed
- ✅ **Testing Framework**: Integration tests and benchmarking tools

### **Phase 2: Mock Implementation - DONE**
- ✅ **Mock RDMA Engine**: Complete Rust implementation for development
- ✅ **Pattern Data Generation**: Predictable test data for validation
- ✅ **Simulated Performance**: Realistic latency and throughput modeling
- ✅ **Development Environment**: Full testing without hardware requirements

---

## 🚀 **PHASE 3: REAL RDMA IMPLEMENTATION**

### **3.1 Hardware Abstraction Layer** 🔴 **HIGH PRIORITY**

#### **Replace Mock RDMA Context**
**File**: `rdma-engine/src/rdma.rs`
**Current**:
```rust
RdmaContextImpl::Mock(MockRdmaContext::new(config).await?)
```
**TODO**:
```rust
// Enable UCX feature and implement
RdmaContextImpl::Ucx(UcxRdmaContext::new(config).await?)
```

**Tasks**:
- [ ] Implement `UcxRdmaContext` struct
- [ ] Add UCX FFI bindings for Rust
- [ ] Handle UCX initialization and cleanup
- [ ] Add feature flag: `real-ucx` vs `mock`

#### **Real Memory Management**
**File**: `rdma-engine/src/rdma.rs` lines 245-270
**Current**: Fake memory regions in vector
**TODO**:
- [ ] Integrate with UCX memory registration APIs
- [ ] Implement HugePage support for large transfers
- [ ] Add memory region caching for performance
- [ ] Handle registration/deregistration errors

#### **Actual RDMA Operations**
**File**: `rdma-engine/src/rdma.rs` lines 273-335
**Current**: Pattern data + artificial latency
**TODO**:
- [ ] Replace `post_read()` with real UCX RDMA operations
- [ ] Implement `post_write()` with actual memory transfers
- [ ] Add completion polling from hardware queues
- [ ] Handle partial transfers and retries

### **3.2 Data Path Replacement** 🟡 **MEDIUM PRIORITY**

#### **Real Data Transfer**
**File**: `pkg/rdma/client.go` lines 420-442
**Current**:
```go
// MOCK: Pattern generation
mockData[i] = byte(i % 256)
```
**TODO**:
```go
// Get actual data from RDMA buffer
realData := getRdmaBufferContents(startResp.LocalAddr, startResp.TransferSize)
validateDataIntegrity(realData, completeResp.ServerCrc)
```

**Tasks**:
- [ ] Remove mock data generation
- [ ] Access actual RDMA transferred data
- [ ] Implement CRC validation: `completeResp.ServerCrc`
- [ ] Add data integrity error handling

#### **Hardware Device Detection**
**File**: `rdma-engine/src/rdma.rs` lines 222-233
**Current**: Hardcoded Mellanox device info
**TODO**:
- [ ] Enumerate real RDMA devices using UCX
- [ ] Query actual device capabilities
- [ ] Handle multiple device scenarios
- [ ] Add device selection logic

### **3.3 Performance Optimization** 🟢 **LOW PRIORITY**

#### **Memory Registration Caching**
**TODO**:
- [ ] Implement MR (Memory Region) cache
- [ ] Add LRU eviction for memory pressure
- [ ] Optimize for frequently accessed regions
- [ ] Monitor cache hit rates

#### **Advanced RDMA Features**
**TODO**:
- [ ] Implement RDMA Write operations
- [ ] Add Immediate Data support
- [ ] Implement RDMA Write with Immediate
- [ ] Add Atomic operations (if needed)

#### **Multi-Transport Support**
**TODO**:
- [ ] Leverage UCX's automatic transport selection
- [ ] Add InfiniBand support
- [ ] Add RoCE (RDMA over Converged Ethernet) support
- [ ] Implement TCP fallback via UCX

---

## 🔧 **PHASE 4: PRODUCTION HARDENING**

### **4.1 Error Handling & Recovery**
- [ ] Add RDMA-specific error codes
- [ ] Implement connection recovery
- [ ] Add retry logic for transient failures
- [ ] Handle device hot-plug scenarios

### **4.2 Monitoring & Observability**
- [ ] Add RDMA-specific metrics (bandwidth, latency, errors)
- [ ] Implement tracing for RDMA operations
- [ ] Add health checks for RDMA devices
- [ ] Create performance dashboards

### **4.3 Configuration & Tuning**
- [ ] Add RDMA-specific configuration options
- [ ] Implement auto-tuning based on workload
- [ ] Add support for multiple RDMA ports
- [ ] Create deployment guides for different hardware

---

## 📋 **IMMEDIATE NEXT STEPS**

### **Step 1: UCX Integration Setup**
1. **Add UCX dependencies to Rust**:
   ```toml
   [dependencies]
   ucx-sys = "0.1"  # UCX FFI bindings
   ```

2. **Create UCX wrapper module**:
   ```bash
   touch rdma-engine/src/ucx.rs
   ```

3. **Implement basic UCX context**:
   ```rust
   pub struct UcxRdmaContext {
       context: *mut ucx_sys::ucp_context_h,
       worker: *mut ucx_sys::ucp_worker_h,
   }
   ```

### **Step 2: Development Environment**
1. **Install UCX library**:
   ```bash
   # Ubuntu/Debian
   sudo apt-get install libucx-dev
   
   # CentOS/RHEL  
   sudo yum install ucx-devel
   ```

2. **Update Cargo.toml features**:
   ```toml
   [features]
   default = ["mock"]
   mock = []
   real-ucx = ["ucx-sys"]
   ```

### **Step 3: Testing Strategy**
1. **Add hardware detection tests**
2. **Create UCX initialization tests**
3. **Implement gradual feature migration**
4. **Maintain mock fallback for CI/CD**

---

## 🏗️ **ARCHITECTURE NOTES**

### **Current Working Components**
- ✅ **Go Sidecar**: Production-ready HTTP API
- ✅ **IPC Layer**: Robust Unix socket + MessagePack
- ✅ **SeaweedFS Integration**: Complete mount client integration
- ✅ **Docker Setup**: Multi-service orchestration
- ✅ **Error Handling**: Comprehensive fallback mechanisms

### **Mock vs Real Boundary**
```
┌─────────────────┐     ┌─────────────────┐     ┌─────────────────┐
│   SeaweedFS     │────▶│   Go Sidecar    │────▶│  Rust Engine    │
│   (REAL)        │     │   (REAL)        │     │   (MOCK)        │
└─────────────────┘     └─────────────────┘     └─────────────────┘
                                                          │
                                                          ▼
                                                 ┌─────────────────┐
                                                 │ RDMA Hardware   │
                                                 │ (TO IMPLEMENT)  │
                                                 └─────────────────┘
```

### **Performance Expectations**
- **Current Mock**: ~403 ops/sec, 2.48ms latency
- **Target Real**: ~4000 ops/sec, 250μs latency (UCX optimized)
- **Bandwidth Goal**: 25-100 Gbps (depending on hardware)

---

## 📚 **REFERENCE MATERIALS**

### **UCX Documentation**
- **GitHub**: https://github.com/openucx/ucx
- **API Reference**: https://openucx.readthedocs.io/
- **Rust Bindings**: https://crates.io/crates/ucx-sys

### **RDMA Programming**
- **InfiniBand Architecture**: Volume 1 Specification
- **RoCE Standards**: IBTA Annex A17
- **Performance Tuning**: UCX Performance Guide

### **SeaweedFS Integration**
- **File ID Format**: `weed/storage/needle/file_id.go`
- **Volume Server**: `weed/server/volume_server_handlers_read.go`
- **Mount Client**: `weed/mount/filehandle_read.go`

---

## ⚠️ **IMPORTANT NOTES**

### **Breaking Changes to Avoid**
- **Keep IPC Protocol Stable**: Don't change MessagePack format
- **Maintain HTTP API**: Existing endpoints must remain compatible
- **Preserve Configuration**: Environment variables should work unchanged

### **Testing Requirements**
- **Hardware Tests**: Require actual RDMA NICs
- **CI/CD Compatibility**: Must fallback to mock for automated testing
- **Performance Benchmarks**: Compare mock vs real performance

### **Security Considerations**
- **Memory Protection**: Ensure RDMA regions are properly isolated
- **Access Control**: Validate remote memory access permissions
- **Data Validation**: Always verify CRC checksums

---

## 🎯 **SUCCESS CRITERIA**

### **Phase 3 Complete When**:
- [ ] Real RDMA data transfers working
- [ ] Hardware device detection functional
- [ ] Performance exceeds mock implementation
- [ ] All integration tests passing with real hardware

### **Phase 4 Complete When**:
- [ ] Production deployment successful
- [ ] Monitoring and alerting operational
- [ ] Performance targets achieved
- [ ] Error handling validated under load

---

**📅 Last Updated**: December 2024
**👤 Contact**: Resume from `seaweedfs-rdma-sidecar/` directory
**🏷️ Version**: v1.0 (Mock Implementation Complete)

**🚀 Ready to resume**: All infrastructure is in place, just need to replace the mock RDMA layer with UCX integration!
