RAIDZ2 vs RAID 6 — 6×12 TB

You have 6 drives of 12 TB (72 TB raw) and are deciding between RAIDZ2 (ZFS double parity with checksums) and RAID 6 (double parity — two drives may fail). The table shows what each choice actually gives you.

MetricRAIDZ2RAID 6
Usable capacity48 TB48 TB
Redundancy overhead24 TB24 TB
Storage efficiency67%67%
Fault tolerance (drives)22
Minimum drives44

Both give the same usable capacity on this configuration — the decision is about failure behavior, not space.

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