Synology DS918+ Storage Upgrade Guide

Comprehensive upgrade strategy for expanding storage capacity and performance on the Synology DS918+ NAS.

Table of Contents

Overview

This document outlines the strategy for upgrading the Synology DS918+ storage infrastructure to support the growing data needs of the homelab environment, including TKG/TAS workloads and general storage expansion.

Key Objectives

  • Expand capacity: From 8TB to 16TB+ usable storage
  • Add redundancy: Migrate from RAID 0 to RAID 1 for data protection
  • Improve performance: Upgrade memory and optimize cache configuration
  • 10G ready: Prepare for 10G network integration

Current Configuration

Storage Layout

  • 2x Western Digital Red Pro 4TB (WD4002FFWX)
    • Configuration: RAID 0 (striped)
    • Usable capacity: 7.3TB
    • Current usage: 5.6TB (80% full)
    • RPM: 7200, Cache: 64MB

Cache Configuration

  • 2x Crucial P3 Plus 500GB NVMe (PCIe Gen4)
    • Total cache: 1TB
    • Configuration: Read/Write cache
    • Previous: 2x Samsung 970 EVO 250GB (replaced)

Memory

  • Slot 1: 4GB (factory installed)
  • Slot 2: 4GB Timetec DDR3L-1866 (D3NS1866L-4G)
  • Total: 8GB DDR3L

Available Bays

  • Bay 3: Empty
  • Bay 4: Empty

Upgrade Strategy

Phase 1: Immediate Expansion (Q2 2025)

Investment: ~$550

Fill empty bays with high-capacity drives while maintaining existing RAID 0 volume.

Benefits

  • Immediate capacity increase without data migration
  • Maintain current performance during transition
  • Test new drives before committing to full migration

Configuration

  • Volume 1: Existing 2x 4TB RAID 0 (7.3TB usable)
  • Volume 2: New 2x 8TB+ RAID 1 (8TB+ usable)
  • Total: 15TB+ usable capacity

Phase 2: Full Migration (Q3-Q4 2025)

Investment: ~$650

Replace existing 4TB drives with larger capacity drives for unified storage pool.

Target Configuration

  • 4x Seagate IronWolf Pro 16TB in SHR-2
  • Usable capacity: 32TB with dual-drive failure protection
  • Performance: Improved with larger cache buffers

Shopping List

High-Capacity Drives

  • Model: ST16000NTZ01
  • Specifications:
    • Capacity: 16TB
    • RPM: 7200
    • Cache: 256MB
    • Workload: 300TB/year
    • Warranty: 5 years + 3 years free data recovery
  • Price: $320-350 each
  • Vendors:
    • Amazon: ~$320-350
    • B&H Photo: Similar pricing
    • Best Buy: Available for pickup

Option 2: WD Red Pro 16TB

  • Model: WD161KFGX
  • Specifications:
    • Capacity: 16TB
    • RPM: 7200
    • Cache: 512MB (larger than Seagate)
    • Workload: 300TB/year
    • Warranty: 5 years
  • Price: $330-360 each
  • Advantage: Larger cache buffer

Phase 1 Shopping List (Immediate)

  1. 2x Seagate IronWolf Pro 16TB: $640-700
  2. Total Phase 1: ~$650

Phase 2 Shopping List (Future)

  1. 2x Additional 16TB drives: $640-700
  2. Total Phase 2: ~$650

Memory Upgrade (Optional)

  • Current: 8GB DDR3L total
  • Upgrade option: Replace one 4GB with 8GB SODIMM
  • Target: 12GB total (4GB + 8GB)
  • Cost: ~$60-80
  • Benefit: Better performance for Docker containers and VMs

10G Network Card

  • Synology E10G18-T1: $120-150
  • Purpose: Connect to 10G network infrastructure
  • Vendors:

Implementation Plan

Phase 1: Capacity Expansion

Week 1: Drive Installation

  1. Order 2x 16TB drives
  2. Install in bays 3 and 4
  3. Initialize as new volume
  4. Configure RAID 1 for redundancy

Week 2: Testing and Migration

  1. Test new volume performance
  2. Begin migrating non-critical data
  3. Validate backup procedures
  4. Monitor drive health and performance

Phase 2: Full Migration (Later)

Preparation

  1. Complete backup of all critical data
  2. Document current configuration
  3. Plan migration schedule for minimal downtime

Migration Process

  1. Add 2 more 16TB drives
  2. Create new SHR-2 volume
  3. Migrate data from old volumes
  4. Remove old 4TB drives
  5. Optimize new configuration

RAID Migration Guide

Current Risk Assessment

  • RAID 0 vulnerability: No redundancy, single drive failure = total data loss
  • Capacity utilization: 5.6TB used of 7.3TB (80% full)
  • Growth projection: Additional 8-10TB needed for TKG/TAS workloads

Migration Strategy Options

  1. Install 2x 16TB drives in empty bays
  2. Create new RAID 1 volume (8TB usable)
  3. Migrate new data to redundant volume
  4. Keep existing RAID 0 for non-critical data
  5. Later: Migrate critical data and rebuild

Option B: Complete Rebuild

  1. Full backup to external storage
  2. Replace all drives with 4x 16TB
  3. Create SHR-2 configuration
  4. Restore all data
  5. Risk: Longer downtime, backup dependency

RAID Configuration Recommendations

SHR-2 (Synology Hybrid RAID)

  • Configuration: 4x 16TB drives
  • Usable capacity: ~32TB
  • Redundancy: Tolerates 2 drive failures
  • Performance: Good read performance, acceptable write

RAID 6 Alternative

  • Configuration: 4x 16TB drives
  • Usable capacity: ~32TB
  • Redundancy: Tolerates 2 drive failures
  • Performance: Similar to SHR-2

Performance Optimization

Cache Configuration

  • Current: 2x 500GB NVMe (1TB total)
  • Optimization: Configure as read/write cache
  • Expected improvement: 20-30% for frequently accessed data

Network Optimization 

# Enable jumbo frames for 10G connectivity
Control Panel → Network → Network Interface
- Enable Jumbo Frame (9000 bytes)

# Optimize SMB performance
Control Panel → File Services → SMB/AFP/NFS
- Enable SMB3 multi-channel
- Large MTU for SMB

Memory Optimization

  • Docker containers: Limit memory usage per container
  • VM allocation: Reserve memory for NAS operations
  • Cache allocation: Allow system to auto-manage

Backup Strategy

Before Migration

  1. Complete backup to external USB drive
  2. Cloud backup of critical data (Synology C2)
  3. Test restore procedures
  4. Document recovery process

Ongoing Backup

  • Snapshot replication between volumes
  • Automated cloud backup for critical data
  • Version control for configuration files
  • Regular backup verification

Cost Analysis

Investment Comparison

Approach Phase 1 Cost Phase 2 Cost Total Usable Capacity Redundancy
Recommended $650 $650 $1,300 32TB Dual-drive
Budget $400 $800 $1,200 24TB Single-drive
Premium $800 $800 $1,600 48TB Dual-drive

Cost per TB

  • Current: $25/TB (no redundancy)
  • Upgraded: $40/TB (with redundancy)
  • Industry standard: $30-50/TB for enterprise NAS

Troubleshooting

Common Issues

Drive Recognition Problems 

# Check drive compatibility
Control Panel → Storage Manager → Storage Pool

# Verify drive health
Control Panel → Storage Manager → Storage Pool → Manage → Health

Migration Performance

  • Expected speed: 100-200MB/s for RAID rebuild
  • Duration: 20-40 hours for 16TB drives
  • Optimization: Schedule during low-usage periods

Capacity Planning

  • Reserve space: Keep 10-15% free for optimal performance
  • Growth planning: Monitor usage trends monthly
  • Cleanup: Regular maintenance of temporary files

Performance Monitoring 

# Monitor storage utilization
Resource Monitor → Storage

# Check cache hit rates
Storage Manager → Storage Pool → Cache

# Network throughput testing
Network Center → Network Interface → Traffic

References

Internal Documentation

External Resources

Last Updated: 2025-01-11 Maintained by: Mark Alston

This project is for educational and home lab purposes.