RAID 0
RAID 0 Quick Facts
What Is RAID 0?
RAID 0 is a striped storage layout. Data is divided into segments and distributed across the member drives instead of being stored entirely on one device. The drives operate together as one logical volume.
Because RAID 0 does not reserve drive capacity for mirroring or parity, the nominal usable capacity is the combined usable capacity of the member drives, limited by the smallest member when drive capacities differ.
Data Is Distributed Across the Drives
A striped workload can use multiple member drives during an I/O operation. Depending on the controller, software implementation, workload, stripe size, queue depth, storage devices, and interface limits, this can increase aggregate read and write throughput compared with a single drive.
Simplified conceptual illustration of data striping.
RAID 0 Usable Capacity
If all drives are the same size, their capacities are combined. If different-size drives are used in a traditional RAID 0 array, capacity above the smallest participating drive's size may not be usable by the array.
Four 4 TB Drives
4 drives × 4 TB = 16 TB nominal RAID 0 capacity.
4 TB + 4 TB + 8 TB
Using the smallest member as the limiting size gives 3 × 4 TB = 12 TB nominal array capacity for the RAID layout.
Why RAID 0 Can Increase Throughput
Because data is distributed across member drives, multiple devices can participate in reads and writes. In favorable workloads, aggregate throughput can be higher than a single drive can deliver.
Performance Does Not Scale Perfectly
Real RAID 0 performance depends on the storage devices, controller or software implementation, stripe size, block size, queue depth, workload, host interface, PCIe bandwidth, CPU overhead, caching, filesystem, and application behavior. Drive count alone cannot guarantee a specific performance gain.
RAID 0 Provides No Drive Fault Tolerance
RAID 0 stores portions of the logical data set across its member drives but does not store parity or mirrored copies. If a member drive fails, the RAID 0 virtual disk fails and the array does not have redundant information from which to rebuild the missing data.
RAID 0 Strengths
- Uses the full nominal active-drive capacity.
- No capacity is reserved for parity.
- No duplicate mirror copy is stored.
- Striping can improve aggregate throughput.
- Relatively simple RAID architecture.
RAID 0 Limitations
- No redundant copy of data.
- No parity protection.
- A member failure causes the RAID 0 virtual disk to fail.
- Not appropriate when RAID-level drive-failure protection is required.
- Backups remain necessary for important data.
When RAID 0 May Be Appropriate
RAID 0 is generally suited to cases where performance or temporary capacity is more important than array-level fault tolerance.
When RAID 0 Is Usually the Wrong Choice
RAID 0 is generally a poor fit when continued operation after a drive failure is a requirement. Production databases, important file repositories, business-critical application storage, primary backup repositories, and other persistent workloads typically require a storage design with appropriate redundancy in addition to a separate backup strategy.
RAID 0 Compared With Other RAID Levels
| RAID Level | Technique | Nominal Capacity | Drive Fault Tolerance | Primary Tradeoff |
|---|---|---|---|---|
| RAID 0 | Striping | N × smallest drive | None | Maximum nominal capacity, no redundancy |
| RAID 1 | Mirroring | One member's capacity | Depends on mirror width | Redundancy at lower capacity efficiency |
| RAID 5 | Striping + single parity | (N − 1) × smallest drive | 1 drive | Capacity efficiency with parity overhead |
| RAID 6 | Striping + dual parity | (N − 2) × smallest drive | 2 drives | Higher redundancy with greater parity overhead |
| RAID 10 | Mirrors + striping | Typically 50% | Topology-dependent | Performance and redundancy with 50% nominal efficiency |
Calculate Your RAID 0 Configuration
Use the Tech Supply Direct RAID Calculator to estimate nominal RAID 0 capacity, storage efficiency, performance assumptions, hardware cost, and compare the result with other RAID levels.
RAID 0 FAQ
Does RAID 0 provide redundancy?
No. RAID 0 uses striping and stores no parity or mirrored copy for drive-failure recovery.
What happens if a RAID 0 drive fails?
The RAID 0 virtual disk fails because part of the striped data set becomes unavailable and there is no redundant information from which to rebuild it.
How much capacity does RAID 0 provide?
Nominal capacity is the number of participating drives multiplied by the capacity of the smallest member.
Is RAID 0 faster than a single drive?
It can provide higher aggregate throughput because I/O can be distributed across multiple drives, but actual gains depend on the workload and hardware implementation.
Is RAID 0 a backup?
No. RAID 0 provides neither backup nor drive redundancy. Important data should exist in an independent backup system.
Can different-size drives be used in RAID 0?
Implementations may permit mixed capacities, but the smallest participating drive generally determines the capacity contribution of each member in a traditional RAID 0 layout.
RAID 0 Documentation
This article is based on established RAID behavior documented by enterprise hardware vendors, including Dell documentation for RAID 0 striping and IBM RAID level documentation.