Yes, you can use redundant array of independent disks (RAID) with solid state drives (SSDs). RAID allows combining multiple disk drives into one logical unit to provide features like redundancy, improved performance, or increased storage capacity compared to single drives.
What is RAID?
RAID stands for redundant array of independent disks. It is a data storage technology that combines multiple physical disk drives into one logical drive to provide redundancy, performance improvements, or capacity expansion compared to single drives. Some key points about RAID:
- RAID takes multiple physical drives and combines them into a single logical drive using specialized RAID controllers.
- There are different RAID levels (RAID 0, 1, 5, 6 etc) that provide different features like striping, mirroring, parity etc.
- RAID provides benefits like increased data redundancy, improved performance, or expanded storage capacity.
- If a physical drive fails in a RAID array, the data can still be recovered from the remaining drives.
- RAID is implemented in both hardware and software solutions.
In summary, RAID provides improved performance, capacity, and resilience by coordinating multiple drives together compared to single disk solutions.
Can SSDs be used in RAID?
Yes, solid state drives (SSDs) can absolutely be used in RAID configurations just like traditional hard disk drives (HDDs). Here are some key points on using SSDs with RAID:
- SSDs provide better performance than HDDs in terms of latency and IOPS. This makes them desirable for use in RAID arrays.
- RAID improves the performance and resilience of SSDs just like with HDD RAID.
- SSDs are compatible with common RAID levels like RAID 0, 1, 5, 10 etc when used with RAID controllers.
- Enterprise SSDs meant for data centers often have power loss protection making them suitable for RAID.
- SSD-based RAID arrays offer faster rebuilding after a disk failure compared to HDD-based RAID.
Overall, SSDs are fully compatible with RAID implementations and are increasingly used in RAID deployments for better performance and reliability compared to HDD-based arrays.
Benefits of using SSD RAID
Using SSDs in RAID configurations offers several benefits compared to using traditional HDDs. Some of the key benefits are:
- Faster performance: SSDs provide much lower latency and higher IOPS than HDDs which results in faster overall performance for the RAID array.
- Improved resilience: Like HDD RAID, SSD RAID provides redundancy and fault tolerance from drive failures.
- Better reliability: SSDs have no moving parts so they tend to be more reliable than HDDs in the long run.
- Lower power consumption: SSD RAID uses less electricity compared to HDD RAID making them suitable for green data centers.
- Faster rebuilding: When rebuilding RAID arrays after a failed drive, SSDs can rebuild much faster than HDDs due to better performance.
By combining the performance of SSDs with the resilience of RAID, SSD RAID arrays offer compelling advantages over HDD-based RAID in many situations.
Types of SSD RAID
SSDs can be used with all the commonly used RAID levels just like HDDs. Some examples include:
- RAID 0: Block level striping SSDs for best performance.
- RAID 1: Mirroring SSDs for 100% redundancy.
- RAID 5: Block level distributed parity for redundancy and read performance.
- RAID 10: Mirrored stripes SSDs for highest performance with redundancy.
- RAID 50: Striped RAID 5 arrays for large storage and redundancy.
Additionally, some RAID levels are better suited for SSD characteristics:
- RAID 1E: Mirrored SSDs with stripe cache for optimized writes.
- RAID 7E: Dedicated hot spare SSD for auto-rebuild after failure.
These RAID levels can maximize some of the unique advantages of SSDs like fast rebuilds and optimized writes.
SSD vs HDD RAID
Comparing SSD RAID arrays to traditional HDD RAID arrays reveals some key differences:
| Factor | SSD RAID | HDD RAID |
|---|---|---|
| Performance | Much faster due to lower latency and higher IOPS of SSDs | Slower performance due to mechanical nature of HDDs |
| Reliability | More reliable with no moving parts in SSDs | HDDs can fail due to mechanical issues |
| Power consumption | Lower power usage, better for green data centers | HDDs consume more power |
| Capacity | Lower capacity than HDD RAID currently | Higher capacity arrays possible with HDDs |
| Cost | More expensive than HDD RAID per GB currently | HDD RAID is cheaper per GB |
In summary, SSD RAID provides better performance and reliability while HDD RAID can provide larger capacity arrays at a lower cost currently. The advantages of SSD RAID make it suitable for performance-critical applications despite higher costs.
Considerations for SSD RAID
Some key considerations when implementing SSD RAID include:
- Use enterprise SSDs for RAID as they are designed for sustained random IO workloads.
- Ensure SSD firmware is optimized for RAID capabilities like TLER and CCTL.
- Match SSD performance to required workload. Fast SSDs can improve array rebuild times.
- Use RAID controllers with TRIM support to optimize SSD garbage collection.
- Enable SSD overprovisioning to extend lifespan and maintain peak performance.
Optimizing firmware, controllers, and SSD settings enables building high performance and reliable SSD RAID arrays.
RAID Controller Considerations
The RAID controller is a critical component when building SSD RAID arrays. Consider these factors when selecting RAID controllers:
- Look for SSD caching support to boost read/write speeds.
- Ensure TRIM support optimizes SSD garbage collection and performance.
- Choose controllers with SAS connections for best SSD performance.
- Seek newer controllers optimized for SSD low latency workloads.
- Consider NVMe RAID cards to maximize next-gen SSD performance.
Advanced RAID cards designed for SSDs can fully unlock the performance capabilities of SSD RAID arrays.
Optimizing OS for SSD RAID
Tuning the operating system is key to maximizing SSD RAID performance. Recommended OS optimizations include:
- Aligning partitions properly for SSD sector sizes.
- Setting TRIM/UNMAP support for garbage collection.
- Enabling write caching and native command queuing.
- Disabling file access time logging to minimize writes.
- Setting partitioning alignment to 1MB offsets.
Optimized OS settings reduce write amplification and latency for better SSD RAID performance.
SSD RAID Use Cases
SSD RAID offers advantages for various use cases including:
- Transactional databases: Fast SSD RAID delivers high IOPS to support heavy database workloads.
- High performance computing: Low latency CPU-SSD data transfers speeds simulations and computations.
- Big data analytics: Large parallel SSD RAID arrays enable fast processing of vast datasets.
- Virtualization: Fast VM provisioning and boot storms made possible by SSD RAID performance.
- Media streaming: High bandwidth SSD RAID delivers smooth streaming of 4K/8K video.
Any application needing high performance, low latency storage can benefit from deploying SSD RAID storage solutions.
Cost considerations
While SSD RAID offers higher performance and reliability than HDD RAID, the cost is higher currently. Some factors to consider:
- SSD costs are dropping steadily, improving TCO of SSD RAID.
- Weigh higher SSD RAID costs vs benefit of application performance gains.
- Use tiering with smaller SSD RAID for hot data and larger HDD RAID for cold data.
- Start with pilot SSD RAID for performance critical workloads first.
- Factor in power, cooling, and footprint savings when comparing TCO.
As SSD pricing evolves, combined SSD/HDD hybrid RAID architectures provide an optimal balance.
Conclusion
SSDs are fully supported for use in all common RAID configurations. SSD RAID combines the performance, resilience, and efficiency benefits of both technologies. Compared to HDD RAID, advantages of SSD RAID include faster IO performance, lower latency, better reliability, and lower power usage. When optimized with the right RAID controllers and OS settings, SSD RAID delivers significant advantages for workloads needing high speed storage access. While SSD RAID has a higher upfront cost, the performance benefits outweigh the costs for many usage scenarios.
