RAID 10 vs. RAID 5: When to use each level and why

RAID is a technology that combines disk arrays in different forms through predetermined configurations or levels to provide better fault tolerance, improved performance, and data storage. This configuration, also called RAID levels, is the way different disks are combined, and this level determines the benefits. Some of the commonly used RAID levels are RAID 0, RAID 1, RAID 5, RAID 6, and RAID 10. There are also other variations depending on the needs of the business.

These RAID levels can be implemented through hardware or software, though most of the higher RAID levels are implemented with hardware for better performance and flexibility.

In this article, we’ll compare RAID 10 and RAID 5 to understand which of the two is better in a given scenario.

What is RAID 10?

raid 10
Wikimedia

RAID 10 is a complex RAID level that combines the configuration and benefits of RAID 1 and RAID 0. In other words:

RAID 10 = RAID 1 + RAID 0

As we all know, RAID 1 mirrors data and duplicates it for improved fault tolerance whereas RAID 0 stripes the volume across multiple disks for better performance.

In RAID 10, the capabilities of both RAID 1 and RAID 0 are combined to give us both fault tolerance and enhanced performance. In this configuration, data is striped evenly across disks, and these are mirrored as well,

Here is a depiction of this RAID.

Advantages

The advantages of RAID 10 are:

  • Offers improved performance.
  • Fast as you can read and write data simultaneously.
  • Provides excellent security.
  • No data loss.

Disadvantages

The disadvantages of RAID 10 are:

  • Only 50 percent of storage capacity can be used because data is mirrored.
  • Expensive as it requires more disks to implement.

RAID 5

RAID 5
Wikimedia

RAID 5 is a configuration that uses data striping with parity, and this combination easily reconstructs data during a disk failure. Also, since the data is not mirrored, it uses the existing storage more efficiently.

Such a setup also balances performance, security, storage, and fault tolerance to give an overall efficient configuration. This balance makes it a popular RAID implementation.

Advantages

The advantages of RAID 5 are:

  • Inexpensive to implement compared with other RAID levels.
  • Provides fast reads because of striping.
  • Offers a good balance between security, fault tolerance, and performance.
  • Highly efficient for data storage.

Disadvantages

The disadvantages of RAID 5 are:

  • Takes a long time to rebuild the data because of parity.
  • Write performance is slow.
  • Complex to implement.

So far, we have seen the two RAID levels and their advantages and disadvantages. Let’s now move on to their comparison.

RAID 10 vs. RAID 5: Which is better?

First off, there is no question of which RAID level is better as each comes with its advantages and disadvantages. It is more about which of the two suits your set up or your goal better for various scenarios.

That said, the biggest difference between RAID 10 and RAID 5 is the way it rebuilds the data. When a disk fails, RAID 10 reads data from the mirror disk and copies the same to the disk you replaced. Hence, there is no change in your read or write operations.

But in a RAID 5 configuration, the disk has to read data from all the other disks, use the parity information spread across the disks, and reconstruct the data. This is time-consuming and puts a higher load on your system, thereby increasing the chances of a system crash or even the failure of other disks.

One area where RAID 5 scores over RAID 10 is in storage efficiency. Since RAID 5 uses parity information, it stores data more efficiently and, in fact, offers a good balance between storage efficiency, performance, and security. RAID 10, on the other hand, requires more disks and is expensive to implement.

These differences can be summarized as follows:

Operations/Features

RAID 10

RAID 5

Minimum number of physical disks required 4 3
Focus area Performance and fault tolerance Storage
Flexible in structure Yes No
Read/Write Faster Fast
Ideal for backup No Yes
Uses parity No Yes
Complexity Low High
Hardware or software implementation Works well on any hardware controller Can be implemented through software or hardware

Now that we have seen the differences, let’s see which RAID level to use in different real-time scenarios.

Real-time scenarios

Some common real-time scenarios where we have to choose a RAID level are described below.

File and application servers

RAID 5 is your best bet for file and application servers with a limited number of drivers as it offers a good balance between storage, performance, security, and resistance to failure.

Focus on read/write operations

When you have applications that require fast read/write operations, RAID 10 is the right choice because it doesn’t manage parity, so no checks are necessary. In fact, the read performance of RAID 10 is twice as fast as RAID 5.

Disk failure

If two or more disks can fail in your setup, RAID 5 is your choice, as it’s not possible to recover data when two or more disks fail at the same time in RAID 10. While the chances for more disks to fail at the same time is minimal, it is still something to consider.

But RAID 10 reconstructs data faster when a single disk has failed, so there’s no impact to read and write operations whereas RAID 5 takes a long time because of parity checks. Also, data is lost for good if the Uncorrectable Read Error (URE) occurs in RAID 5.

In all, RAID 10 is your choice when you want to recover quickly from a disk failure without impacting existing operations.

Budget and cost-effectiveness

If you’re on a budget or want to get the most out of your money, RAID 5 is your choice because RAID 10 requires a minimum of four disks and uses only 50 percent storage capacity.

Complexity

If you want a simple RAID setup or if you’re new to RAID levels and are exploring its benefits, RAID 10 is your choice. You’ll have to simply combine RAID 0 and RAID 1 to get all the benefits. RAID 5, on the other hand, is complex to implement.

Backup

For efficient backup and storage solutions, RAID 5 is the right choice as it is designed for efficient and cost-effective storage. It has two-thirds or four-fifths storage capacity when compared to RAID 10’s 50 percent.

Production and hosting servers

RAID 10 is ideal for production and hosting servers because of its performance and data security. Though it is expensive to implement, it more than makes up for it with its performance and fault tolerance.

RAID 10 works well for database implementations as well.

RAID 10 vs. RAID 5: Now you know

To conclude, RAID 10 combines RAID 0 and RAID 1 to give excellent fault tolerance and performance whereas RAID 5 is more suited for efficient storage and backup, though it offers a decent level of performance and fault tolerance. Of course, RAID 10 is more expensive as it requires more disks whereas RAID 5 is more complex to implement.

Since both the RAID levels have varying advantages and disadvantages, the exact choice depends on the given scenario, cost constraints, expectations, and other pertinent factors.

Do you have any experience implementing RAID 10 or RAID 5? Please share your experience with our readers in the comments section.

Featured image: Shutterstock

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6 thoughts on “RAID 10 vs. RAID 5: When to use each level and why”

  1. “Disk failure
    If two or more disks can fail in your setup, RAID 5 is your choice, as it’s not possible to recover data when two or more disks fail at the same time in RAID 10.”

    I think you have this the wrong way around in this quote. RAID 10 with 4 disks can survive the loss of 2 disks, if you’re lucky and only lose one side of each mirror. If RAID 5 loses 2 disks it’s dead regardless.

  2. Nick is 100% correct. Lose two drives in a Raid 5 config and you’re gone. Personal experience there.. Other piece to add with Raid 5 is that all 4 drives should be identical down to firmware levels and versions levels.

    1. “Other piece to add with Raid 5 is that all 4 drives should be identical down to firmware levels and versions levels.”

      Why’s that?

  3. Please learn your theory before writing article advising people on RAID.
    RAID 5 can experience unrecoverable error even if 1 disk fails when the parity strip was not updated on time (no battery backup RAID controller).
    if RAID 5 loses 2 disks it’s unrecoverable where RAID 10 has 50/50 chance to survive loss of 2 disks if 4 disks are attached and 25% chance to survive 3 failed disks if 6 or more disks are attached. On your downside for RAID 10 – available space, today’s servers have greater need of bandwidth & performance. Speed is everything, unless you are stuck in 1970’s. E.g. Raid 10 gives you 2x(number of the disks) read and 0.5x(number of the disks) write performance. My 8 disks in RAID 10 do give me 8x the read performance and 4x the write performance (0.9Gb/s Read & 0.6Gb/s Write for non SSD’s, and 4Gb/s Read & 2Gb/s Write). My MySQL is very happy on RAID 10 and no so happy on RAID 5 with 65k+ user requests per second.

  4. Thanks Dimitar_V for the gems you shared. It is really sad to see people with no clear ideas of raid are writing articles and people are deciding on given information.

  5. I think the article was fairly good, apart from the mistake on the number of drives that can fail. Perhaps it was an honest mistake, rather than ignorance?

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