My Storage Rabbit Hole: What I Learned While Trying to Build the “Perfect” Backup System

Backups are supposed to give you peace of mind. Instead, over the last few weeks, they gave me homework.

It started with a warning on macOS:

Disk Not Recommended for Backups – AFP over NAS will not be supported in a future version of macOS.

Translation: my beloved, ancient Apple Time Capsules were headed for retirement. They have been flawlessly backing up my Macs for years, quietly doing their job. But macOS Tahoe made it clear: the world has moved on.

So I began the search for a replacement.

Step 1: NAS vs DAS vs Hybrid

Before this project, I assumed storage was storage. Wrong. The storage world is full of categories, opinions, and trade-offs.

A NAS does not behave like an external drive. A DAS does not behave like a server. Most devices are designed to specialize in one role, not both.

Step 2: Drive speed vs network speed

I spent a lot of time comparing network options (1 GbE vs 2.5 GbE vs 10 GbE) before realizing the real question was: what speeds can the drives themselves deliver?

Approximate real-world drive speed:

Approximate real-world network throughput:

The realization was simple:

• 2.5 GbE is the ideal match for mechanical hard drives.
• 10 GbE only makes sense if using SSD or NVMe storage.

Step 3: The hidden danger of reusing old drives

I originally planned to reuse my two old 6 TB drives and delay buying new ones. Then I discovered something important:

The most dangerous moment in an old drive’s life is when it is under full read/write stress, such as during data migration or RAID creation.

The safe upgrade approach:

1. Buy one new NAS-rated drive first.
2. Install only that new drive in the NAS.
3. Copy data slowly from old drives.
4. After data is copied, repurpose old drives as secondary/offline backup.
5. Later, buy another new drive and expand to RAID-1 or RAID-5.

This prevents both old drives from being stressed at the same time.

Step 4: USB ports on a NAS do not mean “DAS mode”

I assumed that if a NAS had USB ports, I could plug it directly into my Mac like an external drive.

On most NAS units, USB ports are only for attaching external drives to the NAS, not for connecting the NAS to a computer. The NAS remains a network device and must be accessed over SMB or NFS.

Only certain models with USB QuickAccess or Thunderbolt NAS features support direct connection, and even then, the drives are usually accessed over a virtual network instead of behaving as true DAS.

What storage architecture fits which use case?

The decision I finally made

My priorities were:

• Quiet
• Low power consumption
• Dependability
• Multiple Macs backing up automatically through Time Machine
• Minimal long-term maintenance

The answer:

A NAS with 2.5 GbE and new NAS-rated drives.

Not 10 GbE.
Not Thunderbolt DAS.
Not a device trying to be both at once.

The real lesson was not about choosing the “best” technology, but about matching drive speed, network speed, and workflow in a realistic way.

Final notes to future me

• Replace one old drive before it fails.
• 2.5 GbE is the best match for hard drives.
• 10 GbE only makes sense with SSDs or NVMe.
• USB on a NAS does not turn it into a DAS.
• Choose NAS for multi-device backups and automation.
• Choose DAS for maximum performance to a single machine.

Closing thoughts

I began this journey trying to recreate the simplicity of Apple’s Time Capsule. Modern storage is more complicated, but the end result is better:

• Modern
• Reliable
• Quiet
• Future-proof
• And suited to how I actually use my computers

If sharing this helps someone else avoid a week of research, spec sheets, and contradictory forum posts, then it was worth the journey.