Part 8: DIY UNRAID NAS: Preparing the Zero-Downtime NVMe Upgrade (512GB -> 4TB)

DIY UNRAID NAS Part 8: Preparing the Zero-Downtime NVMe Upgrade

Welcome back to Hancock’s VMware Half Hour and to Part 8 of the DIY UNRAID NAS build series.
In this episode, I walk through the planning and preparation for a zero-downtime NVMe cache
upgrade on my homelab UNRAID NAS, running on an Intel NUC 11 Extreme.

The goal of this two-part upgrade is to move from a single 512 GB XPG NVMe cache device
to a pair of Samsung 990 PRO 4 TB NVMe SSDs, ending up with a high capacity Btrfs RAID 1
cache pool for VMs, Docker, and PCIe passthrough workloads. Part 8 focuses on the design,
constraints, and first hardware changes. Part 9 completes the migration and final Btrfs rebalance.

Video: DIY UNRAID NAS Part 8

You can watch the full episode on YouTube here:

DIY UNRAID NAS – Part 8: Preparing the Zero-Downtime NVMe Upgrade

What This Episode Covers

Part 8 is all about understanding the current environment, identifying limitations in UNRAID,
and laying the groundwork for a non-destructive storage upgrade. In the video, I cover:

How my UNRAID array and cache devices are currently configured.
The future hardware specifications for the homelab UNRAID NAS.
Plans for using enterprise U.2 NVMe devices in future expansions.
Why we cannot simply create another cache pool in UNRAID to solve this.
A staged plan to replace the old 512 GB XPG NVMe with 4 TB Samsung 990 PRO drives.
How to safely stop Docker and virtual machines before making hardware changes.
Using PCIe passthrough (VMDirectPath I/O) to present NVMe devices directly to a Windows 11 VM.
Updating Samsung 990 PRO firmware from within the passthrough VM using Samsung Magician.
Confirming that all Samsung NVMe drives are genuine and authenticated.
Reviewing the NVMe slot layout in the Intel NUC 11 Extreme (2 x Gen 3 and 2 x Gen 4).

Chapter Breakdown

Here is the chapter list from the video for quick navigation:

00:00 – Intro
00:05 – Welcome to Hancock’s VMware Half Hour
00:47 – This is Part 8 DIY UNRAID NAS
01:21 – Explanation of UNRAID and how I have set up UNRAID
04:20 – Explanation of UNRAID array and cache devices
04:51 – Future specifications for homelab UNRAID NAS
05:54 – Future use of enterprise NVMe U.2 device
09:42 – I have a cunning plan says Andy
12:02 – We cannot create another cache pool
12:56 – Stop Docker and VMs
13:10 – Shutdown ESXi on UNRAID
13:28 – Shutdown Windows 11 on UNRAID
14:22 – New NVMe installed, old XPG removed
15:16 – PCIe passthrough demonstration configuration for UNRAID VMs
17:14 – Restart NAS
17:29 – NVMe devices are enabled for PCI passthrough
18:11 – VMware VM Direct I/O (PCI passthrough) explained
18:46 – Configure Windows 11 VM for PCI passthrough
20:00 – Samsung Magician advising firmware update available
20:48 – Update firmware of Samsung 990 PRO from Windows 11
23:14 – Confirmation that all Samsung NVMe are authenticated
26:22 – NVMe slots in Intel NUC 11 Extreme are 2 x Gen 3 and 2 x Gen 4
27:06 – Remove NVMe devices from Windows 11 VM

The Cunning Plan: A Staged, Non-Destructive NVMe Upgrade

The key challenge in this build is upgrading from a 512 GB NVMe cache to larger 4 TB devices
without wiping the array or losing data. Because UNRAID cannot create an additional cache pool
in this configuration, we need a staged process.

In Part 8, I outline and begin the following upgrade path:

Review the current UNRAID array and cache configuration.
Plan the future target: dual 4 TB NVMe Btrfs RAID 1 cache pool.
Shut down Docker and VM services cleanly.
Power down the NAS and remove the old XPG NVMe.
Install the first Samsung 990 PRO 4 TB NVMe drive.
Boot the system and confirm the new NVMe is detected.
Use PCIe passthrough to present the NVMe to a Windows 11 VM for firmware checks and updates.
Update NVMe firmware using Samsung Magician and validate that the drive is genuine.

The actual Btrfs pool expansion and final dual-drive RAID 1 configuration are completed
in Part 9, where the second 4 TB NVMe is installed and the cache pool is fully migrated.

PCIe Passthrough and Firmware Updates

A significant part of the episode is dedicated to demonstrating PCIe passthrough
(VMDirectPath I/O) from VMware ESXi into UNRAID and then into a Windows 11 virtual machine.
This allows the Samsung 990 PRO NVMe to be exposed directly to Windows for:

Running Samsung Magician.
Checking for and applying firmware updates.
Verifying drive health and authenticity.

This approach is particularly useful in homelab environments where the hardware is
permanently installed in a server chassis, but you still want to access vendor tools
without moving drives between physical machines.

Intel NUC 11 Extreme NVMe Layout

Towards the end of the video, I review the NVMe slot layout inside the Intel NUC 11 Extreme.
This platform provides:

2 x PCIe Gen 4 NVMe slots.
2 x PCIe Gen 3 NVMe slots.

Understanding which slots are Gen 3 and which are Gen 4 is critical when deciding where to place
high performance NVMe devices such as the Samsung 990 PRO, especially when planning for
future workloads and potential enterprise U.2 NVMe expansion.

What Comes Next in Part 9

Part 8 ends with the new 4 TB NVMe installed, firmware updated, and the environment ready
for the next stage. In Part 9, I complete the migration by:

Replacing the remaining 512 GB cache device with a second 4 TB Samsung 990 PRO.
Rebuilding the Btrfs cache pool as a dual-drive RAID 1 configuration.
Verifying capacity, redundancy, and performance.

If you are interested in UNRAID, NVMe-based cache pools, or nested VMware and PCIe
passthrough in a small form factor system like the Intel NUC 11 Extreme, this two-part
upgrade is a practical, real-world example of how to approach it safely.

andysworld!