What is RAID 60?
RAID 60 is a type of RAID (Redundant Array of Independent Disks) configuration that combines multiple RAID levels to provide fault tolerance and improve performance. Specifically, RAID 60 uses a combination of RAID 6 and RAID 0.
RAID 6 provides double parity, meaning the array can sustain the failure of up to two drives without losing data. RAID 0 stripes data across multiple disks for improved performance.
By combining these two RAID levels, RAID 60 aims to deliver fast performance while also providing protection against two disk failures. The tradeoff is that more disks are required compared to a single RAID level.
What are the benefits of RAID 60?
There are several potential benefits to using RAID 60:
– Fault tolerance – With dual parity, RAID 60 can withstand the failure of up to two disks without data loss. This makes it more tolerant against disk failures than RAID 5 or RAID 6 alone.
– Performance – By striping data across multiple disks, RAID 60 can provide faster read/write speeds compared to a single disk or other RAID levels like RAID 6. The performance boost comes from increased bandwidth.
– Capacity – In a RAID 60 array with the same number of disks, you get more usable storage capacity compared to RAID 10. This is because RAID 10 duplicates all data, while RAID 60 uses parity.
– Rebuild times – Rebuilding a RAID 60 array after a failed drive is faster than rebuilding a RAID 6 array, since the rebuild process can be distributed across more disks.
What are the downsides of RAID 60?
There are also some potential downsides to weigh:
– Complexity – RAID 60 is more complex to implement and manage than a single RAID level. The probability of a configuration error or incompatibility issue rises with complexity.
– Cost – Implementing RAID 60 requires a minimum of 8 drives, making it more expensive than RAID 6 or RAID 10. More disks means higher costs for the initial purchase as well as ongoing maintenance and power requirements.
– Decreased capacity – Due to the dual parity requirement, RAID 60 offers less usable capacity compared to RAID 6 with the same number of disks.
– No distributed parity – Unlike RAID 6, RAID 60 does not distribute the parity strips across drives. This can impact rebuild times and performance compared to RAID 6.
When is RAID 60 recommended over other RAID levels?
RAID 60 works best in specific situations:
– For mission critical storage with high capacity and performance needs. The combination of improved performance and dual parity makes RAID 60 well-suited for applications where downtime is unacceptable.
– For large arrays with high likelihood of multiple disk failures. With more disks, the chance of dual disk failures rises. RAID 60 provides an extra safeguard.
– When sequential read/write performance is more important than random I/O. The striping of RAID 0 delivers gains in sequential transfers.
– When the cost of multiple disks is acceptable for higher performance and redundancy. RAID 60 is overkill for budget-conscious storage needs.
How does RAID 60 compare to RAID 10?
Both RAID 10 and RAID 60 provide fault tolerance and improved performance, but they differ in their approaches:
| RAID 10 | RAID 60 |
|---|---|
| Mirroring and striping | Striping over dual RAID 6 arrays |
| Can tolerate failure of up to 1 disk per mirrored pair | Can tolerate failure of up to 2 disks in the array |
| Requires minimum 4 disks | Requires minimum 8 disks |
| 50% redundancy – doubles storage requirements | Parity based redundancy |
| Faster rebuilds than RAID 60 | Slower rebuilds than RAID 10 |
| Lower usable capacity than RAID 60 | Higher usable capacity than RAID 10 |
In summary, RAID 10 is faster and simpler but less efficient in capacity. RAID 60 provides more usable storage and allows larger arrays, at the cost of slower rebuilds.
What are recommended RAID 60 array configurations?
Popular RAID 60 setups include:
– 8 data disks with 2 parity disks, which can survive 2 failed drives.
– 12 data disks with 4 parity disks, allowing survival of up to 4 disk failures.
– 16 data disks with 6 parity disks, providing the dual parity protection for even larger arrays.
The minimum number of disks for RAID 60 is 8 – with 6 data disks and 2 for parity. A larger number of data disks will improve performance by increasing the stripe size.
The total number of disks should be a multiple of 2 to permit even distribution across the dual RAID 6 sets. For optimal performance, all the disks should be of the same size and speed.
What steps are needed to implement RAID 60?
The process for creating a RAID 60 array is:
1. Assemble the physical disks that will make up the array into the server or enclosure. All disks should be the same size and speed for optimal performance.
2. Configure two separate RAID 6 arrays in the RAID controller BIOS or software. For example, disks 1-4 could be RAID 6 array 1 and disks 5-8 RAID 6 array 2.
3. Create a RAID 0 array that stripes across the two RAID 6 arrays. This completes the RAID 60 configuration.
4. Initialize and format the RAID 60 array with the desired file system (e.g. EXT4, XFS, NTFS).
5. Mount the RAID 60 array on your operating system so it is available as storage.
6. Populate the array with your data or backups. Monitor the status of the disks and arrays using your RAID management tools.
What maintenance practices are recommended for RAID 60 arrays?
To maximize the lifespan and performance of a RAID 60 array:
– Monitor disk health metrics like SMART status and immediately replace any suspect or failed drives.
– Keep firmware and drivers updated on RAID controllers to fix bugs and improve compatibility.
– Periodically monitor array parity consistency to detect silent data corruption.
– Follow manufacturer guidelines for RAID controller cache settings, stripe size, and disk replacement procedures.
– Provide adequate cooling, power delivery, and vibration damping in the server or enclosure.
– Consider hot spare disks to allow automatic rebuilding after a failure.
– Schedule regular backups in case multiple disk failures exceed the fault tolerance of RAID 60.
What are the failure scenarios in a RAID 60 array?
RAID 60 can survive the following failure scenarios with no data loss:
1. Up to 2 disk failures in a single RAID 6 set. The dual parity allows any 2 failed disks to be reconstructed.
2. 1 disk failure in each of the RAID 6 sets. Each set can handle a single failure, allowing survival of 2 total failed disks.
3. Loss of a single RAID controller with the drives daisy chained to a secondary controller. No data loss since all disks are still accessible.
4. Rebuilding of the array after replacing up to 2 failed disks. The parity data will regenerate the missing data.
Scenarios that would cause RAID 60 failure and potential data loss:
1. 3 or more concurrent disk failures in a RAID set before replacements can be installed. Exceeds the dual parity protection.
2. Failure of multiple disks during rebuilds after previous disk failures. The stress of rebuilding may cause additional faults.
3. Catastrophic RAID controller failure without daisy chaining to secondary controller. Total array becomes inaccessible.
4. Unrecoverable bit errors on multiple disks exceeding the redundancy capabilities of RAID 6 and RAID 60.
Conclusion
RAID 60 can provide performance and redundancy benefits for mission critical storage, but at increased cost and complexity compared to single RAID level configurations. It is best suited for workloads that demand high capacity, fast throughput, and maximum fault tolerance against disk failures.
RAID 60 works by combining the performance of RAID 0 striping with the dual parity protection of RAID 6. This provides fast speed but requires a minimum of 8 disks. Compared to RAID 10, it offers greater usable capacity but slower rebuilds.
The decision between RAID 60, RAID 10, or other RAID levels depends on the requirements, budgets, and risks of a specific storage environment. RAID 60 makes sense for large arrays where downtime is unacceptable and the expense of multiple disks is warranted. It provides an extra layer of protection compared to RAID 6 alone.
However, the added complexity of RAID 60 also increases the risks of misconfiguration and compatibility issues. Proper implementation, monitoring, and maintenance practices are critical to realizing the benefits of uptime and performance. For less demanding environments, single RAID levels like RAID 10 or RAID 6 may provide sufficient redundancy at lower costs.