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StashRaid

Storage Parameters

Usable Capacity

12 TB

Fault Tolerance

4

Array Resilience

Architecture

RAID 5 • Parity

Fault Tolerance

1 Concurrent Failures Allowed

Current Configuration

RAID 5 (Parity)

12 TB Usable

Total RAW: 16 TB

Disk 01DATA
Disk 02DATA
Disk 03DATA
Disk 04PARITY

Total Drives

4 x 4 TB

Efficiency

75% Utilized

Usable: 12 TBWasted to redundancy: 4 TB

Pros & Cons

  • PRO: Good balance of capacity/speed/safety

  • PRO: Cost-effective redundancy

  • CON: Slower writes due to parity calculation

    This setup prioritizes redundancy but has associated performance or capacity costs.

Backup Strategy for RAID Users

If you run a RAID array, you already understand redundancy — but redundancy is not a backup. This guide explains why RAID alone is dangerous, how to build a 3-2-1 backup strategy for your NAS, and which cloud and local options give you the best protection.

Why RAID Is Not a Backup

RAID protects against drive failure. But consider:

  • Accidental deletion — A single rm -rf or drag-to-trash is immediately replicated across all disks. Gone in seconds.
  • Ransomware — Encrypted blocks are mirrored to every drive. Every copy gets locked simultaneously.
  • Fire, flood, or theft — All drives share one enclosure. A single physical event destroys every copy regardless of RAID level.
  • Software bugs & silent corruption — Bit-rot or filesystem bugs corrupt data on all drives before RAID detects the problem.
  • Controller failure — A dead hardware controller with proprietary on-disk formatting can make all drives unrecoverable.

Bottom line: RAID handles hardware failure; backups handle everything else.

The 3-2-1 Backup Rule for NAS Environments

The 3-2-1 rule is the gold standard. Applied to a NAS:

3 Copies

Your live data (1), a local backup (2), and an off-site copy (3).

2 Media Types

Mix media: HDD + SSD, or HDD + cloud object storage.

1 Off-Site

Cloud, friend's house, or colocation — physically separate from the primary NAS.

Backup Tier Architecture

TierTargetRTORPOCostProtects Against
Tier 1External USB HDD / Secondary NASMinutes1–24 hours$ (one-time HDD cost)Accidental deletion, ransomware, software bugs
Tier 2Remote NAS / rsync targetHours1–24 hours$ (NAS + drives + network)Fire, flood, theft (same city)
Tier 3Cloud cold storage (S3 Glacier, B2)12–48 hours1–7 days$$ ($1–6/TB/mo)Site-wide disaster (fire, flood, theft)

Cloud Backup Options Compared

ProviderCostEgressRestore SpeedBest For
Backblaze B2$6/TB/mo$10/TB (first 3x free)Fast (download or 1-day hard drive ship)Home NAS & Prosumer
AWS S3 Glacier Deep Archive$1/TB/mo$9/TB + retrieval fees12–48 hours (or $$ expedited)Cold archival / compliance
Wasabi Hot Cloud$6.99/TB/mo (no egress)FreeFast (S3-compatible download)Active backup with frequent restores
Google Cloud Storage Archive$1.23/TB/mo$12/TB24+ hours (or $$ expedited)Enterprise cold storage

Backblaze B2 is the best balance of cost and restore speed for home NAS users. For archival data, S3 Glacier Deep Archive at $1/TB/mo is unbeatable.

Ransomware-Proofing Your Backups

Ransomware is the #1 threat to NAS backups. Protect your backups with:

  • Immutable backups — S3 Object Lock or ZFS read-only snapshots prevent modification.
  • Air-gapped rotation — Keep an offline drive disconnected except during backup windows.
  • Versioned backups — rsync --link-dest or Borg/Restic dedup for daily, weekly, monthly snapshots.
  • Separate credentials — Backup service accounts with limited-permission API keys, no write access to shares.

Snapshot Replication

Most NAS platforms support incremental transfers of ZFS or Btrfs snapshot deltas to a remote target. Synology Snapshot Replication works on Btrfs volumes with hourly snapshots. TrueNAS / ZFS send/receive transfers only changed blocks with encryption and compression — your fastest path to off-site recovery.

Frequently Asked Questions

If I have RAID, why do I still need backups?

RAID protects against drive failure only. It does not protect against accidental deletion, ransomware, software bugs, power surges, fire, flood, or theft. Backblaze found 47% of data loss is from human error, not hardware failure. RAID + backups is the only complete strategy.

What is the 3-2-1 backup rule, and how does it apply to a NAS?

3 copies of your data, on 2 different media types, with 1 copy off-site. For a NAS: (1) live RAID data, (2) local USB or secondary NAS backup, (3) cloud backup to B2 or S3 Glacier. The off-site copy is critical for ransomware, fire, and theft scenarios.

Can I use cloud storage as my only backup?

Cloud-only is risky — downloading terabytes takes days or weeks. A hybrid approach (local for fast restoration, cloud for disaster recovery) gives both speed and safety. Budget 1–2 months of egress costs into your restoration plan.

How do snapshots fit into a backup strategy?

Snapshots are point-in-time copies on the same array. They protect against accidental deletion and ransomware (roll back to pre-encryption state) but not array failure or physical disasters. Use hourly snapshots as a first line, then layer on real backups to external targets.

Optimize Your RAID First

Optimize your primary storage before setting up backup targets. Model your configuration with our calculators.

RAID Calculator SHR Calculator ZFS Calculator