A RAID (Redundant Array of Independent Disks) card is a piece of hardware that connects to the motherboard and controls multiple hard drives or solid-state drives (SSDs). The main purpose of a RAID card is to combine multiple drives together into a RAID array which can improve performance, capacity, or reliability compared to a single drive.
RAID cards allow you to configure your drives into different RAID levels like RAID 0, 1, 5, or 10 which have specific benefits. For example, RAID 0 spreads data across multiple drives for faster performance while RAID 1 mirrors drives for redundancy. The RAID card manages the distribution of data across the array.
Using RAID with SSDs can provide benefits like increased read/write speeds or protection against drive failure. However, SSDs also have some unique characteristics that may reduce the usefulness of a RAID card in some scenarios. This article will examine if a RAID card is necessary to setup a RAID array with SSDs.
Overview of SSDs
SSDs stands for Solid State Drives. Unlike traditional hard disk drives (HDDs) that use magnetic platters and a mechanical arm to read/write data, SSDs use flash memory chips to store data with no moving parts (1). This gives SSDs significant speed, durability, silence, and energy efficiency advantages over HDDs.
Specifically, SSDs use NAND flash memory chips to persistently store data. These chips allow very fast access times for reading and writing data compared to the mechanical components in HDDs. SSDs also have no latency delays from physical actuation, allowing much faster access. Overall, this means SSDs can achieve faster boot times, quicker application/file loads, and improved overall system responsiveness versus HDDs (2).
Additionally, because SSDs lack moving parts, they are more resistant to shock, run silently, and have lower power consumption. However, HDDs still have advantages in maximum capacity and price per gigabyte.
Sources:
(1) https://www.crucial.com/articles/about-ssd/ssd-vs-hdd
(2) https://www.pcmag.com/news/ssd-vs-hdd-whats-the-difference
Benefits of Using a RAID Card with SSDs
Using a RAID card with SSDs can provide several benefits compared to using the drives individually without RAID. Some key advantages include:
Increased performance – Configuring multiple SSDs in a RAID 0 array can provide significant performance improvements compared to a single SSD, since the reads and writes are spread across multiple drives. This allows for faster access times and higher overall throughput.1
Redundancy – RAID levels like 1, 5, and 6 provide redundancy by duplicating data across multiple drives. This protects against data loss if a single SSD fails. The RAID continues operating using the remaining disks until the failed unit is replaced.
Improved reliability – In addition to redundancy, RAID detects and can correct more errors than a single SSD, improving overall reliability. This makes RAID with SSDs well-suited for mission critical applications.
Convenience – A hardware RAID card neatly handles the RAID tasks like striping and mirroring. The drives appear as a single logical volume to the operating system. This provides easy management compared to configuring software RAID.
Automated rebuilding – If an SSD in a RAID fails, the RAID card automatically rebuilds the array once the failed drive is replaced. This occurs transparently without user intervention.
Caching – Many RAID cards include onboard caching to further accelerate performance. This provides an extra speed boost for random reads and writes.
Downsides of Using a RAID Card with SSDs
There are some potential downsides to using a dedicated RAID card with SSDs:
Added cost – RAID cards add to the overall cost of the system. Consumer SSDs without a RAID card may provide adequate performance at a lower price point for some use cases (Source).
Complexity – RAID cards add complexity to the system build and configuration. Setting up and managing software RAID may be easier for some users.
Limited features – Some enterprise-level SSD features like power loss protection may not be supported on consumer RAID cards. The RAID card could become a bottleneck (Source).
In summary, RAID cards add cost, complexity, and may offer limited feature support compared to enterprise SSDs designed for RAID environments. The benefits of a RAID card need to be weighed against these potential downsides for each use case.
When a RAID Card Makes Sense for an SSD Setup
A RAID card can provide important benefits for an SSD setup when you have a large array, critical data, and a need for redundancy. With a large number of SSDs, a dedicated RAID card helps manage the array and improves performance through techniques like striping (https://www.enterprisestorageforum.com/hardware/ssd-raid-boosting-ssd-performance-with-raid/). The RAID card offloads processing overhead from the main CPU/OS, allowing for faster speeds.
For mission critical data and applications where uptime is essential, RAID gives redundancy and protection against drive failures. RAID 1 mirroring provides a real-time backup SSD that can seamlessly takeover if one SSD fails. More advanced RAID levels like 5 and 6 provide parity data that allows rebuilding a failed drive. This is critical for minimizing downtime and avoiding data loss (https://www.reddit.com/r/sysadmin/comments/aavir0/do_you_still_set_up_raid_for_ssd_drives/).
In summary, RAID cards are most useful for SSD arrays in mission-critical environments that demand maximum performance, capacity, and fault tolerance.
When a RAID Card is Unnecessary for an SSD Setup
SSDs already offer significant reliability improvements over traditional HDDs, so utilizing a RAID configuration becomes less critical in certain scenarios. For example, if you’re only running a small number of SSDs or have a limited budget, investing in a dedicated RAID card may not make sense.
For budget-focused builds where maximum uptime and redundancy aren’t absolute requirements, you can rely on the RAID capabilities integrated into many motherboards and operating systems. This approach skips the extra cost of a hardware RAID card.
Likewise, RAID cards become overkill in setups dealing with non-critical data that doesn’t necessitate fault tolerance and accelerated rebuild times. If you can easily recreate lost data, the benefits of a RAID card diminish compared to simply letting the operating system or motherboard handle SSD management.
According to a thread on Reddit, RAID cards are more relevant when “you need to protect your data, squeeze more performance out, or require additional connectivity.” With just a few SSDs in a basic home or office PC, the hassle and cost of a dedicated RAID card is often unwarranted (source).
Recommended RAID Levels for SSDs
There are four RAID levels that are commonly recommended for SSD setups:
RAID 0
RAID 0 spreads data evenly across all the disks in the array with no redundancy (Source: https://www.enterprisestorageforum.com/hardware/ssd-raid-boosting-ssd-performance-with-raid/). This allows for maximum read and write speeds since the workload is balanced across multiple disks. However, it offers no fault tolerance – if one disk fails, all data will be lost. RAID 0 works best for maximizing SSD performance in non-critical storage scenarios.
RAID 1
RAID 1 mirrors data between two disks, providing full redundancy (Source: https://larryjordan.com/articles/maximize-performance-with-an-ssd-raid/). This protects data and ensures continuity of operations if a disk fails. However, RAID 1 cuts the total capacity in half. Performance is decent but not as fast as RAID 0. RAID 1 is a good option when data protection is critical.
RAID 5
RAID 5 stripes data across disks with distributed parity information that allows for one disk failure tolerance (Source: https://community.spiceworks.com/topic/1146565-what-is-the-best-raid-for-ssd-on-a-server). It provides a balance of speed, capacity, and fault tolerance. However, rebuilding the array after a disk failure can be slow. RAID 5 is a versatile option for SSD arrays.
RAID 10
RAID 10 mirrors data while also striping it across disks for performance (Source: https://www.enterprisestorageforum.com/hardware/ssd-raid-boosting-ssd-performance-with-raid/). This provides the speed of RAID 0 plus the fault tolerance of RAID 1. However, capacity is limited to 50% of the total disks. RAID 10 is ideal when both performance and redundancy are critical.
Software vs Hardware RAID for SSDs
When setting up RAID with SSDs, you have the choice between software RAID and hardware RAID. There are tradeoffs to consider with each approach:
Software RAID relies on RAID functionality built into the operating system or third-party software. The main advantage of software RAID is flexibility – you can combine SSDs of different sizes and interfaces, and freely adjust the RAID configuration (1). Software RAID also works with any SSDs and doesn’t require specialized hardware. However, software RAID can have higher CPU overhead compared to hardware, and may offer less advanced feature sets. Stability can also depend on the specific software solution used.
Hardware RAID uses a dedicated RAID controller card for managing the RAID. This offloads RAID calculations from the main CPU. Hardware RAID typically offers better performance, especially for heavy workloads. The dedicated hardware can also enable more advanced features like onboard caching. However, hardware RAID controllers are more rigid and offer less flexibility in drive selection and configuration changes compared to software (2). Hardware RAID also carries an additional upfront cost for purchasing the RAID card.
Overall, software RAID provides more flexibility while hardware RAID offers better performance and advanced features. For SSDs, software RAID is often sufficient unless you specifically need the advantages of a hardware RAID card.
Top RAID Cards for SSDs
When choosing a RAID card to use with SSDs, some top recommendations include:
LSI MegaRAID SAS 9361-8i
- Supports up to 240 SSDs with expanders
- RAID levels 0, 1, 5, and 6
- 12Gb/s data transfer speed
- Cache memory: 1GB DDRIII RAM
ATTO ExpressSAS H1244
- Supports up to 244 SSDs
- RAID levels 0, 1, 4, 5, 6, 10, 50 and 60
- 12Gb/s data transfer rate
- Cache memory: 2GB DDR3 RAM
HighPoint RocketRAID 2720SGL
- Supports up to 8 SSDs without expanders
- RAID levels 0, 1, 10, 5, 50
- Up to 6Gb/s data transfer speed
- 512MB DDR3 onboard cache memory
Conclusion
In summary, whether you need a RAID card for your SSD setup depends on several factors:
– If you are looking for increased performance, redundancy, or easy drive management, a RAID card can provide benefits for an SSD array.
– Hardware RAID cards offer better performance and reliability versus software RAID.
– However, SSDs already provide fast speeds and built-in redundancy. So for a basic single drive or mirrored/striped 2-drive SSD setup, a RAID card may not be necessary.
– RAID 5 or 10 are recommended RAID levels for SSD arrays to optimize performance and redundancy.
– When building a large, high-performance SSD array (e.g. with 4+ drives), a RAID card is recommended to maximize the full potential of the SSDs.
– For mission-critical data or heavy workloads, a hardware RAID card can provide peace of mind through increased data protection and recovery capabilities.
– Make sure to choose a RAID card specifically optimized for SSDs, with features like TRIM/SMART support and SSD caching.
The decision depends on your budget, performance needs, and data protection requirements. Analyze your specific use case before investing in a RAID card for your SSD setup.
