Network Attached Storage (NAS) devices have become increasingly popular for home and business users who need a centralized place to store and access files over a local network or the internet. When setting up a NAS, one of the most important considerations is which RAID level to use for the hard drives inside the NAS enclosure.
RAID 10 is a popular choice for NAS systems because it provides a good balance of performance, capacity, and fault tolerance. However, RAID 10 is not necessarily the best RAID type for every user’s needs. In this article, we’ll examine the pros and cons of using RAID 10 for NAS and look at some alternatives to help you determine if RAID 10 is a good fit for your use case.
What is RAID 10?
RAID 10 is a nested or hybrid RAID level that combines aspects of RAID 1 (mirroring) and RAID 0 (striping) for increased performance and fault tolerance:
- Like RAID 1, RAID 10 makes an exact copy (mirror) of data across two drives.
- Like RAID 0, RAID 10 stripes data across mirrored pairs of drives for faster reads and writes.
For example, in a four-drive RAID 10 array, data will be mirrored across the first and second drives, and also mirrored across the third and fourth drives. The mirrored pairs are then striped together in a RAID 0 configuration.
This layout allows RAID 10 to continue operating normally if one drive fails in each mirrored pair. However, losing both drives in a mirrored set will result in data loss. At least four drives are required for a RAID 10 array.
Benefits of Using RAID 10 for NAS
Here are some of the major advantages of using RAID 10 for network attached storage:
High Performance
One of the biggest upsides of RAID 10 is excellent read and write speeds for both sequential and random operations. By striping data across multiple mirrored drive pairs, the workload can be distributed across all the drives for faster access. This makes RAID 10 a great choice when you need a high-performance NAS for tasks like video editing, media streaming, virtualization, and gaming.
Good Fault Tolerance
With RAID 10, your data remains safe if one drive fails in each mirrored set. The remaining healthy drive in each pair continues to provide access to data. RAID 10 can withstand multiple drive failures so long as no more than one failure occurs per mirrored set. This provides good protection against drive failure.
Faster Rebuilds
When a drive does fail in a RAID 10 array, rebuilding the RAID set after replacing the failed drive is faster compared to other multidrive RAID levels. Because data is mirrored between drives, the NAS only needs to rebuild the data that was stored on the failed drive, not the entire array. This allows your NAS to get back to normal operation quickly.
Twice the Read Performance of RAID 1
While RAID 1 mirrors data to two drives for redundancy, reads only come from one drive at a time. With RAID 10, reads can be distributed across all drives for double the read performance of RAID 1. So if you have a workload that is very read-heavy, RAID 10 will provide faster speeds than RAID 1.
Downsides of Using RAID 10 for NAS
Using RAID 10 for your NAS does come with some tradeoffs and disadvantages:
Less Overall Storage Capacity
Because RAID 10 requires data to be mirrored across drives, it offers less overall storage capacity compared to RAID 5 or RAID 6. With four 2TB drives, for example, a RAID 10 array would only provide 4TB of usable space. RAID 5 or RAID 6 would provide 6TB from the same four drives.
Costlier Than RAID 5 or RAID 6
The drive mirroring in RAID 10 means you need a minimum of four drives. More drives means a higher overall storage cost for your NAS. With higher capacity drives, RAID 10 can be expensive to set up. RAID 5 provides redundancy with only three drives, while RAID 6 can use four drives but gives you more usable capacity than RAID 10.
No Parity Protection
Unlike RAID 5 and RAID 6, RAID 10 does not use parity information to detect and correct errors. The redundancy comes solely from mirroring data between drives. So if both drives in a mirrored set fail, the data on that set cannot be rebuilt using parity as a backup.
When to Use RAID 10 for NAS?
Given its advantages and disadvantages, here are some good use cases for deploying RAID 10 in a NAS:
You Need High Performance
If you need high speeds for managing and accessing large files, streaming high-bitrate media, running virtual machines, or other demanding applications, RAID 10 is a great fit. The performance advantages outweigh the increased storage cost.
Your Data Changes Frequently
RAID 10 handles write-intensive workloads better than RAID 5 or RAID 6, making it ideal for frequently changing data. The faster rebuilds are also beneficial if data is changing often.
You Have 4+ Drives Available
You need a minimum of four drives for RAID 10, so it’s a good match if you have four or more drives to work with. This allows you to take advantage of RAID 10 benefits like fast rebuilds and the ability to withstand multiple drive failures.
You Need Fast Rebuild Times
Because RAID 10 only has to rebuild the data from one failed drive, it offers faster rebuild times than other RAID levels. If your NAS hosts business-critical data that needs to be accessible at all times, RAID 10 can minimize downtime.
You’re Willing to Sacrifice Capacity for Speed
RAID 10 provides less overall space compared to RAID 5 or 6, but offers much faster operation. If you have performance needs that outweigh the need for maximum storage capacity, then RAID 10 is likely the better choice.
Alternatives to RAID 10 for NAS
While RAID 10 is a popular choice for NAS, it’s not the only option. Here are some alternatives with their own pros and cons:
RAID 1
RAID 1 mirrors data between two drives for redundancy. It provides excellent read performance and simple mirroring, but slower writes compared to RAID 10. RAID 1 is a good option if you only have two drives for your NAS.
RAID 5
RAID 5 stripes data across three or more drives and uses distributed parity information for redundancy. It offers good performance and more usable capacity than RAID 10, but rebuild times are slower. RAID 5 provides an efficient option if you need both space and redundancy.
RAID 6
Similar to RAID 5, RAID 6 stripes data across four or more drives with distributed parity. The key difference is RAID 6 uses two parity drives instead of one, allowing it to withstand the loss of up to two drives. This comes at the cost of lower write speeds compared to RAID 5 or RAID 10.
JBOD (Just a Bunch of Disks)
JBOD combines all your drives into one large volume without any redundancy or performance benefits. While this maximizes usable space, it leaves your data unprotected from drive failures. JBOD is only recommended for non-critical data.
ZFS
The ZFS file system offers advanced fault tolerance features like data integrity checks, snapshots, and SSD caching. ZFS provides an alternative way to get redundancy without traditional hardware RAID. However, it requires more system resources than RAID.
Choosing the Right RAID Level for Your Needs
Determining whether RAID 10 is a good choice for your NAS ultimately depends on your specific needs:
- Performance-focused: If you need high speeds for media, virtualization, etc., RAID 10 is likely the best option.
- Balanced storage and redundancy: For a good mix of capacity and fault tolerance, consider RAID 5 or RAID 6.
- Maximum capacity: If storage space is most important, JBOD will give you the largest volume, though without redundancy.
- Advanced features: For advanced capabilities like snapshots and caching, ZFS is worth considering.
You should also make sure you have the appropriate number of drives – RAID 10 requires a minimum of four drives, while RAID 5 and 6 need at least three and four, respectively. The size and speed of your drives will also impact performance.
Benchmarking different RAID configurations with your drives can help identify the best setup for your specific use case. It also helps to plan for future expansion – a RAID level that meets your current needs may not work as well as your storage demands grow.
Summary – The Pros and Cons of RAID 10 NAS
To summarize the key points about using RAID 10 for network attached storage:
Pros:
- Excellent performance for reads and writes
- Good fault tolerance
- Faster rebuilds than other RAID levels
- Ideal for applications that demand speed
Cons:
- Less overall capacity versus RAID 5/6
- Minimum 4 drives required
- No parity protection like RAID 5/6
- More expensive than some alternatives
For the right situation, RAID 10 can be an excellent choice for NAS storage. Its performance and redundancy make it well-suited for high demand use cases. But it also carries a higher cost than other options. Considering your specific storage needs and setup will enable you to determine if RAID 10 is the best fit.
Conclusion
RAID 10 can provide robust performance, fault tolerance, and quick rebuilds for NAS devices when configured properly. However, the lower overall capacity and higher cost make it less ideal for users prioritizing storage space over speed. RAID 5 or RAID 6 often offer a better balance for general home and business use. In the end, selecting the RAID level comes down to matching your specific requirements with the strengths and limitations of each option.
