Building Your Own NAS: The TrueNAS Scale Guide

A NAS (Network Attached Storage) is a computer dedicated to storing files. You can buy a Synology, but building one works better and is cheaper per terabyte.

The OS: TrueNAS Scale

TrueNAS Scale is free, Linux-based (Debian), and uses the ZFS file system.

Why ZFS? (The Secret Sauce)

ZFS is an enterprise filesystem. It detects bit rot.

• Scenario: A cosmic ray flips a bit in your family photo on a normal drive. You open it 5 years later, and it's corrupted.
• ZFS Solution: ZFS checksums every block. When you read the file, it verifies the checksum. If it doesn't match, and you have redundancy (RAID), it auto-heals the file from the parity data.

Hardware Requirements

• CPU: Needs 64-bit. Avoid ancient CPUs that lack AES-NI (encryption).
• RAM: ZFS loves RAM for caching (ARC). 8GB is the minimum; 16GB is comfortable.
• Drives: DO NOT use SMR (Shingled Magnetic Recording) drives. They cause array rebuilds to fail. Use CMR (Conventional Magnetic Recording) drives like WD Red Plus.

The RAID Layout

Don't use RAID 5. In ZFS terms:

1. Stripe: No redundancy (RAID 0). Dangerous.
2. Mirror: Copy data to two drives (RAID 1). 50% capacity, high speed.
3. RAID-Z1: One drive parity (RAID 5). Good for small arrays.
4. RAID-Z2: Two drive parity (RAID 6). Recommended. Any 2 drives can fail without data loss.

The 3-2-1 Backup Rule

A NAS is NOT a backup. If your house burns down, the NAS burns too.

• 3 Copies of data.
• 2 Different media.
• 1 Offsite (Cloud Backblaze or a drive at a friend's house).

Quiz

Conclusion

Owning your data is freedom. A TrueNAS box gives you terabytes of cloud-independent storage. It's safe, fast, and yours.