The choice between RAID 0 and RAID 1 rarely arrives as abstract theory; it lands when you are specifying volumes for a specific machine. A workstation for video editing wants the fastest possible throughput from two disks, and someone proposes striping them. A boot or database volume in a rack server has to keep running when a disk dies overnight, so the spec calls for a mirror. A small two-bay office NAS presents the same fork as a single decision. In every case the same pair of drives can be wired for opposite goals, and choosing the wrong one is expensive to unwind once real data is already sitting on the array.
Three factors decide it, and they pull against each other. The first is fault tolerance: RAID 0 has none, so losing any single member drive destroys the entire array, while RAID 1 keeps serving as long as one mirror copy survives. The second is usable capacity — striping returns 100% of the raw disk you bought, mirroring returns 50%. The third is access pattern: a mirror can serve reads from either disk for a near-doubling of read throughput, but every write must land on both members, capping write speed near one drive. What almost never decides it is which level is 'newer'; the RAID framework dates to the late-1980s Berkeley work, and neither of these two levels has meaningfully changed since — both are decades-old, stable concepts rather than evolving technologies.
At a glance
Side by side
| Factor | RAID 0 | RAID 1 |
|---|---|---|
| Primary goal | Maximum speed and full capacity | Redundancy — survive a drive failure |
| Fault tolerance | None — any single drive loss ends the array | Survives loss of all but one mirror member |
| Minimum drives | 2 | 2 |
| Usable capacity | 100% of raw (sum of all drives) | 50% of raw (standard two-drive mirror) |
| Read performance | Scales with drive count (parallel stripe reads) | Up to ~2x a single drive with read balancing |
| Write performance | Scales with drive count (parallel stripe writes) | Capped near single-drive speed |
| After a drive fails | No rebuild — data is gone, restore from backup | Copy from surviving partner — fast, low risk |
| Array-level failure risk | Higher than one lone disk (risk multiplies) | Far lower — built to absorb a single failure |
| Typical fit | Scratch/temp volumes, disposable speed work | OS/boot and database volumes needing uptime |
Choose RAID 0 when
- The data is disposable — render scratch, transcode caches, or temporary files you can regenerate or restore within minutes.
- You need the maximum sequential throughput that two or more drives can deliver, such as scrubbing a high-bitrate video timeline.
- Every gigabyte of raw capacity must stay usable and there is no budget to spend half of it on a duplicate mirror copy.
- A separate, tested backup already holds the authoritative copy, so an array-ending failure means a restore rather than a loss.
Choose RAID 1 when
- The volume must survive a single disk failure — OS and boot disks, or a database that cannot take an unplanned outage.
- You want the simplest, lowest-risk rebuild: the controller just copies the surviving partner, with no parity to recalculate.
- Read-heavy workloads can serve requests from either mirror member, and write speed near a single drive is acceptable.
- Continuity matters more than capacity, and paying with half the raw disk to avoid downtime is a trade you accept.
Bottom line
For anything whose loss would interrupt work, choose RAID 1: it exists specifically to survive the single most common storage event, a drive failure, and its rebuild is fast and low-risk because the controller only re-copies one surviving partner rather than reading an entire set. Reserve RAID 0 for volumes that are genuinely disposable or fully backed up elsewhere, where speed and full capacity justify running with zero fault tolerance — remembering that striping makes an array-ending failure more likely than a single lone disk, not less. If you need both speed and redundancy on four or more drives, the real answer is usually RAID 10, which stripes across mirrored pairs. And whichever you choose, treat it as availability, never as backup — RAID cannot undo deletion, corruption, or ransomware, all of which it faithfully copies to every member.
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FAQ
Common questions
- Is RAID 1 a backup, or do I still need a separate backup?
- No — RAID 1 is not a backup, and you still need a separate one. A mirror protects against exactly one thing: a physical drive failing. It does nothing against accidental deletion, file corruption, ransomware, theft, fire, or a controller or power failure that kills both disks at once, and it faithfully copies any bad write to every member. Authoritative guidance treats backup as a distinct control: CISA promotes the 3-2-1 rule (three copies, on two media types, with one offsite), and NIST SP 800-53 CP-9 and NIST CSF PR.DS-11 require tested, protected backups separate from disk redundancy.
- Should I use RAID 0 or RAID 1 for gaming, video editing, or a home NAS?
- It depends on whether the data is disposable. For a gaming rig, the games are re-downloadable, so many builders accept RAID 0 (or no array) for load-time speed — a striped failure just means reinstalling. For active video editing, RAID 0 across fast drives gives the throughput a high-bitrate timeline needs, provided your source footage lives safely elsewhere. For a home NAS holding the only copy of family photos or business files, choose a redundant level — RAID 1 on a two-bay unit, or a nested level on larger ones — because that data is not disposable and a drive will eventually fail.
- Does RAID 1 actually double my read speed?
- Sometimes, but not always, and never for writes. Because both drives in a mirror hold identical data, a controller with read load-balancing can service separate read requests from each disk in parallel, approaching roughly twice single-drive read throughput. That gain depends on the controller and the workload — many concurrent reads benefit most, while a single sequential read may not. Writes see no speedup at all: every write must complete on both mirror members before it is acknowledged, so write throughput stays capped near a single drive's speed rather than scaling the way RAID 0 striping does.
- What's the difference between RAID 10 and RAID 01?
- They sound alike and share the same four-drive minimum and 50% usable capacity, but their fault tolerance differs materially. RAID 10 stripes across mirrored pairs: it can survive a failure in every pair at once, as long as no single pair loses both members. RAID 01 mirrors two stripe sets, and there one drive failure takes an entire stripe — half the array — offline, leaving you far more exposed to a second failure anywhere in the surviving half. RAID 10 is the preferred layout wherever a controller supports it; RAID 01 is generally treated as a legacy fallback.