Synology DS918+ Hardware Upgrade Guide

This guide covers upgrading your Synology DS918+ with additional RAM and hard drives.

Table of Contents

RAM Upgrade: Adding 4GB DDR3L SODIMM

Compatible RAM Specifications

The DS918+ requires specific RAM to function properly:

  • Type: DDR3L (Low Voltage) SODIMM
  • Speed: 1600MHz or 1866MHz
  • Voltage: 1.35V
  • Form Factor: 204-pin SODIMM
  • ECC: Non-ECC Unbuffered

Pre-Installation Checklist

  • Backup your data
  • Schedule downtime (initial boot takes ~20 minutes)
  • Have a Phillips screwdriver ready
  • Ensure clean, static-free workspace

Installation Steps

1. Power Down Completely 

# From DSM interface:
Control Panel → Hardware & Power → Shut Down
  • Wait for all LEDs to turn off
  • Disconnect power cable
  • Wait 30 seconds

2. Access Memory Slots

  1. Remove all drive trays (note their positions)
  2. Turn the unit upside down
  3. Locate the memory access panel (small rectangular cover)
  4. Remove the screws securing the memory panel

3. Install the Memory Module

  1. Locate the slots: The DS918+ has 2 SODIMM slots
  2. Installation order:
    • Slot 1: Your new 4GB module
    • Slot 2: Original Synology 4GB module
  3. Insert the module:
    • Align the notch in the module with the notch in the slot
    • Insert at a 45-degree angle
    • Push down until the clips snap into place
    • IMPORTANT: Push firmly until fully seated

4. Reassemble and Boot

  1. Replace the memory access panel
  2. Reinsert all drive trays in original positions
  3. Reconnect power cable
  4. Press power button

5. First Boot Process

  • Initial boot: Takes approximately 20 minutes
  • Memory test: Automatic, may take 1-2 hours
  • During memory test, NAS access is limited
  • Blue LED will blink during testing

Verification 

# After boot, verify in DSM:
Control Panel → Info Center → General
# Should show "Physical Memory: 8 GB"

Storage Expansion: Adding Seagate IronWolf 8TB Drives

Compatibility Note

The DS918+ (released before 2021) is fully compatible with third-party drives including Seagate IronWolf series. You’ll also get access to IronWolf Health monitoring features.

Pre-Installation Checklist

  • Backup existing data
  • Note current RAID configuration
  • Plan for rebuild time (8-12 hours per TB)
  • Ensure drives are same size or larger than existing drives (for SHR)

Physical Installation

1. Prepare the System 

# Optional but recommended:
Storage Manager → Storage Pool → Actions → Safe Shutdown
  • Power down the DS918+
  • Disconnect all cables

2. Install the Drives

  1. Pull out empty drive trays (likely bays 3 and 4)
  2. For 3.5” drives (tool-free installation):
    • Remove the plastic fastening panels from sides of tray
    • Place drive in tray with connectors facing rear
    • Snap fastening panels back into place to secure drive
    • No screws needed for 3.5” drives

3. Reinsert and Power On

  1. Slide drive trays back until they click
  2. Reconnect all cables
  3. Press and hold power button to turn on

Storage Pool Expansion

1. Access Storage Manager 

Main Menu → Storage Manager

2. Expand Existing Pool (SHR Configuration)

  1. Go to Storage Pool page
  2. Select your existing storage pool
  3. Click Action → Add Drive
  4. Select the new drives (they should appear as “Unallocated”)
  5. Click Next through the wizard
  6. Review settings and click Apply

3. Monitor Progress

  • Expansion starts automatically
  • View progress in Storage Manager
  • Expected time: 8-12 hours per TB
  • System remains accessible during expansion (reduced performance)

Alternative: Create New Storage Pool

If you want separate storage pools:

  1. Storage Manager → Storage Pool → Create
  2. Select Better performance or Higher flexibility
  3. Select the new drives
  4. Choose RAID type (SHR recommended)
  5. Follow wizard to completion

Important Considerations

RAM Upgrade Warnings

  1. Warranty: Memory upgrade may void warranty
  2. Memory Test Duration: Can take 1-2 hours with limited NAS access
  3. Maximum RAM: While officially 8GB, users report 16GB (2x8GB) works
  4. DDR3 vs DDR3L: Must use DDR3L (low voltage) - regular DDR3 won’t work

Storage Expansion Warnings

  1. Drive Size Requirements (SHR):
    • New drives must be ≥ size of smallest existing drive
    • For optimal expansion, use same size as largest drive
  2. Rebuild Risk: Small chance of failure during rebuild - ensure backups
  3. Performance Impact: System slower during expansion/rebuild
  4. Time Estimate:
    • 8TB drive rebuild: 8-12 hours
    • Full 4-drive expansion: 24-48 hours

Best Practices

  1. Backup First: Always backup critical data before hardware changes
  2. UPS Recommended: Use UPS during expansion to prevent power loss corruption
  3. Temperature Monitoring: Watch temps during rebuild (should stay <50°C)
  4. Don’t Interrupt: Never power off during memory test or RAID rebuild

RAID 1 vs SHR Comparison

RAID 1 and SHR (Synology Hybrid RAID) with two drives are functionally identical in terms of data protection and storage capacity:

RAID 1:

  • Mirrors data across both drives
  • Provides 50% usable capacity (one drive’s worth)
  • If one drive fails, data remains intact on the other
  • Simple, widely supported standard

SHR with 2 drives:

  • Also mirrors data across both drives
  • Also provides 50% usable capacity
  • Also protects against single drive failure
  • Synology’s proprietary implementation

The key difference emerges when you expand beyond two drives. RAID 1 remains limited to mirroring pairs, while SHR allows more flexible expansion - you can add drives of different sizes and it will optimize the available space. With just two drives though, SHR essentially operates as RAID 1 under the hood.

If you’re only planning to use two drives and might move to non-Synology hardware later, RAID 1 offers better portability. If you’re sticking with Synology and might expand with mismatched drive sizes, SHR provides more flexibility for future growth.

Post-Upgrade Optimization

  1. Enable IronWolf Health:

    Storage Manager → HDD/SSD → Select IronWolf drive → Health Info → IronWolf Health

  2. Set up RAM Monitoring:

    Resource Monitor → Settings → Enable RAM usage alerts

  3. Configure Email Alerts:

    Control Panel → Notification → Email → Enable notifications

Troubleshooting

RAM Issues

  • Blinking blue LED: Reseat memory module
  • Not detecting 8GB: Swap slot positions
  • Won’t boot: Remove new module, boot with original only

Drive Issues

  • Drive not recognized: Check tray is fully inserted
  • Expansion fails: Check drive compatibility and health
  • Slow performance: Normal during rebuild - be patient

Support Resources

This project is for educational and home lab purposes.