RAID 50 vs RAID 60
What Is the Main Difference Between RAID 50 and RAID 60?
RAID 50 stripes across multiple RAID 5 groups, with each group protected by single parity and able to tolerate one failed member drive. RAID 60 stripes across multiple RAID 6 groups, with each group protected by dual parity and able to tolerate up to two failed member drives.
RAID 50 generally provides greater usable capacity and less parity overhead for the same group layout. RAID 60 gives up additional capacity and write efficiency in exchange for stronger protection during drive failures and rebuilds.
RAID 50 vs RAID 60 at a Glance
| Characteristic | RAID 50 | RAID 60 |
|---|---|---|
| Nested Architecture | RAID 0 across RAID 5 groups | RAID 0 across RAID 6 groups |
| Minimum Drives | 6 | 8 |
| Parity Per Group | Single parity | Dual parity |
| Guaranteed Failures Per Group | 1 drive | 2 drives |
| Capacity Formula | G × (D − 1) × smallest drive | G × (D − 2) × smallest drive |
| Capacity Efficiency | Higher | Lower due to second parity equivalent |
| Small-Write Parity Overhead | Lower | Higher |
| Protection After First Failure in a Group | No additional member-failure tolerance in that group | One additional member failure can be tolerated |
Stripe Across Single-Parity Groups
RAID 50 creates multiple RAID 5 groups and places a top-level stripe across them. Each underlying RAID 5 group distributes one parity value and can tolerate the failure of one member drive.
Stripe Across Dual-Parity Groups
RAID 60 follows the same nested concept but uses RAID 6 groups. Each underlying group maintains two independent parity values and can tolerate up to two member-drive failures.
RAID 50 and RAID 60 Differ Inside Each Group
RAID 50 vs RAID 60 Usable Capacity
In these formulas, G is the number of underlying parity groups and D is the number of drives in each group. RAID 50 consumes one drive-equivalent per group for parity, while RAID 60 consumes two.
RAID 50 vs RAID 60 With Twelve 8 TB Drives
To make the comparison consistent, assume two equal six-drive parity groups for each RAID level.
2 × (6 − 1) × 8 TB = 80 TB
2 × (6 − 2) × 8 TB = 64 TB
RAID 50 vs RAID 60 Fault Tolerance
One Failure Per RAID 5 Group
Each underlying RAID 5 group can tolerate one failed member. Multiple simultaneous failures can be survived if they are distributed so that no RAID 5 group loses more than one drive.
Two Failures Per RAID 6 Group
Each underlying RAID 6 group can tolerate up to two failed members. Multiple groups may therefore experience failures simultaneously as long as no individual group exceeds two failed member drives.
Do Not Describe Either Level With One Simple Array-Wide Failure Number
Consider a two-group RAID 50. It can potentially survive two simultaneous drive failures if one failed member is located in each RAID 5 group. Two failures concentrated in the same RAID 5 group can exceed that group's single-parity protection.
A two-group RAID 60 can potentially survive four simultaneous failures if no more than two occur in either RAID 6 group. Three failures concentrated in one group can exceed that group's dual-parity protection. Failure placement therefore matters for both nested RAID levels.
The Affected Group Has No Remaining Drive-Failure Tolerance
Once a RAID 5 group inside RAID 50 has lost one member, that group has exhausted its parity protection until redundancy is restored. A second required member failure in the same group can cause that group, and therefore the RAID 50 virtual disk, to fail.
One Additional Drive Failure Can Still Be Tolerated
After the first member failure within a RAID 6 group, RAID 60 still retains one additional drive-failure tolerance inside that group. This is one of the most important practical resilience differences between RAID 50 and RAID 60.
Is RAID 50 Faster Than RAID 60?
RAID 50 generally has less parity work to perform because each underlying group maintains one parity value instead of two. However, RAID level alone does not determine actual throughput or IOPS.
Both RAID 50 and RAID 60 can provide strong aggregate read throughput because reads are distributed across multiple parity groups and drives.
RAID 50 maintains single parity in each group. RAID 60 maintains dual parity, increasing the work required for parity-sensitive write operations.
Both nested levels can gain performance from striping across multiple independent parity groups. Controller, drive count, media, cache and workload determine how much parallelism is actually realized.
RAID 60 Performs More Parity Work
For partial-stripe writes, parity RAID can require existing data and parity to be read before updated parity is calculated and written. RAID 50 performs this work within RAID 5 groups using single parity. RAID 60 performs it within RAID 6 groups using two independent parity values.
This does not translate into a universal percentage difference in performance. Modern controllers, write-back cache, full-stripe writes, SSD media, queue depth and workload patterns can all substantially alter observed results.
Rebuild Within the Affected RAID 5 Group
A failed RAID 50 member is reconstructed from the surviving data and parity within its RAID 5 group. While that group is degraded, it has no remaining member-drive failure tolerance.
Dual Parity Preserves an Additional Failure Margin
RAID 60 also rebuilds within the affected underlying group, but RAID 6 dual parity means the group still has protection against one additional member failure after the first drive has failed.
More Usable Capacity per Parity Group
RAID 50 sacrifices one drive-equivalent per group instead of two. For the same drive count and group layout, that produces more usable capacity and can lower the hardware cost required to reach a target usable capacity.
More Redundancy per Parity Group
RAID 60 uses the additional parity capacity to preserve protection after the first drive failure in a group. The extra hardware cost therefore purchases fault tolerance rather than usable storage.
RAID 50 or RAID 60: Which Should You Choose?
The choice depends on whether the storage design places greater value on capacity efficiency and lower parity overhead or on additional fault tolerance within every underlying parity group.
- Capacity efficiency is a major priority.
- Single-drive protection per group meets the design requirement.
- Lower parity write overhead is desirable.
- The array is designed around smaller RAID 5 groups.
- Backups and recovery procedures provide additional protection.
- Two-drive fault tolerance per group is important.
- Arrays use large-capacity drives.
- Rebuild windows may be lengthy.
- Maintaining protection after the first failure is a priority.
- Additional parity capacity and write overhead are acceptable.
Common RAID 50 and RAID 60 Use Cases
Compare RAID 50 and RAID 60 With Your Drives
Use the Tech Supply Direct RAID Calculator to compare usable capacity, storage efficiency, parity overhead, fault tolerance, estimated performance, hot-spare impact and hardware cost across RAID 50, RAID 60 and other RAID levels.
RAID 50 vs RAID 60 FAQ
Which has more usable capacity, RAID 50 or RAID 60?
For the same number of groups, drives per group and drive capacities, RAID 50 provides more usable capacity because it consumes one drive-equivalent per group for parity instead of two.
Which has better fault tolerance?
RAID 60 provides greater group-level fault tolerance because each RAID 6 group can tolerate up to two failed members, compared with one per RAID 5 group in RAID 50.
Can RAID 50 survive two drive failures?
It can if the failures occur in different RAID 5 groups. Two failures within the same underlying RAID 5 group can exceed that group's single-parity protection.
Can RAID 60 survive four drive failures?
A two-group RAID 60 can potentially survive four failures if no more than two failed drives occur in either group. Failure placement matters.
Is RAID 50 faster than RAID 60?
RAID 50 generally has less parity write overhead because its groups maintain one parity value instead of two. Actual performance depends on the controller, drives, cache, group layout and workload.
Are RAID 50 and RAID 60 backups?
No. Both provide drive-failure redundancy, but neither replaces an independent and tested backup strategy.
Related RAID Resources
RAID 50 and RAID 60 Are Not Backups
RAID redundancy protects against supported combinations of member drive failures. It does not protect against every cause of data loss, including accidental deletion, corruption, ransomware, application errors, catastrophic system loss or other failures. Important data should also be protected with independent, tested backups.