What is RAID 50 vs RAID 10?
RAID 50 stripes two RAID 5 arrays while RAID 10 stripes two RAID 1 arrays. The next questions would be: what is striping? what is RAID 5 and what is RAID 1? I will answer these questions and more in this tutorial.
In this tutorial you will learn:
- Meaning of RAID?
- What RAID 5 is
- Meaning of RAID 1
- What RAID 0 is
- How RAID 5 is combined with RAID 0 to create RAID 50
- How RAID 1 is combined with RAID 0 to create RAID 10
- Compare benefits and disadvantages of RAID 50 and RAID 10
What is RAID?
RAID means Redundant Array of Independent Disks; formally Redundant Array of Inexpensive Disks). It is a technology that allows you to store your data across multiple disks. The primary purpose of to create redundancy (reduce risk of data loss) and increas performance.
What is RAID 5 and RAID 0?
To understand RAID 50, you need to know how RAID 5 and RAID 0 works. The reason is simple. RAID 50 is created by combining 5 and 0.
While RAID 0 is disk striping without parity, RAID 5 is disk striping with distributed parity. This is best illustrated using diagrams.
Refer to the diagram above. The first thing to note is that you need a minimum of 2 physical disks to create disk striping without parity. From the diagram above, when you stripe Disk 0 and Disk 1, you create a single volume double the size of the smallest disk.
Disk striping offers improved speed (performance). For example, when you stripe 2 disks,the resultant RAID disk is 2 times faster as it combines the speed of both disks.
The downside of RAID 0 is that it does not provide redundancy. Failure of one disk may lead to loss of the entire volume. This may lead to data loss.
Bear in mind that we are discussing striping without and with parity to prepare you to understand RAID 50. In the next section, I will be explaining how RAID 5 works.
In comparison to RAID 0, RAID 5 (striping with distributed parity) requires a minimum of 3 disks. The diagram above illustrates how striping with distributed parity works. Ap, Bp and Cp are parity information. Parity data provides fault tolerance.
As you may have noticed, the parity information is distributed across the 3 disks. What this meas is that if one disk fails you can use the parity information stored in the remaining 2 disks to rebuild the array.
This brings us to the main benefit of a RAID 5 array – fault tolerance. The likelihood of losing data is slim. You can only lose the array if you lose 2 disks at the same time.
In conclusion, one disadvantage of RAID 5 array is that the total volume you get for storage is the size of two disks. This is reason for this is because one disk is always reserved for parity information. The minimum physical disks required for striping with distributed parity is 3.
RAID 50 Explained
Now that you understand how the two RAID levels used to create RAID 50 works it is very easy to understand how RAID 50 works.
In a lay mans language, RAID 50 simply means striping 2 RAID 5 arrays. RAID 50 is sometimes described as RAID 5 + 0. In a RAID 50 configuration, the 2 RAID 5 arrays are treated as individual disks.
RAID 50 requires a minimum of 6 physical disks. The total volume available for storage is the size of 4 disks. In each of the RAID 5 arrays, two disks store parity information.
Advantages and Disadvantages of RAID 50
RAID 50 combines the know benefits of RAID 5 and RAID 0. Remember one of the benefits of RAID 0? Improved performance. I did mention that in this configuration, the combined (stripped volume) multiplies the speed of the disks. This results in improved speed.
I also said that RAID 5 offers improved data redundancy and ability to rebuild the volume using parity information.
If you put the 2 benefits to create a RAID 50, you can conclude that RAID 50 offers greater performance and better redundancy.
One known disadvantage of RAID 5 + 0 is that it requires very complex RAID Controller hardware to implement. It also leads to “loss” of two physical hard disks.
RAID 10 (RAID 1 + RAID 0)
In this part of the tutorial I will cover RAID 10. In the previous section, I already explained RAID 0 (striping without parity). However, to understand RAID 10, you need to understand how RAID 1 works as well.
What is RAID 1?
RAID 1 is known as disk mirroring. Disk mirroring means that data is written to two disks at the same time.
In a RAID 1 configuration, the data in Disk 0 is written to Disk 1. It clearly offers redundancy. Meaning that if one physical disk fails, you will not lose your data. Moreover, if you replace the failed disk you can rebuild the array.
However, RAID 1 has some clear disadvantages. In the first place, the volume offers half the size of the disks that make up the array. This is because same data is written to both disks. Now, if you are writing to two disks, it will clearly lead to reduced write speed as well.
RAID 10 Explained
RAID 10 is stripping (RAID 0) two sets of mirrored arrays (RAID 1).
From the diagram above, you can see two sets of mirrored disks combined to create a stripped disk.
The benefit of RAID 10 is that it offers the data redundancy of RAID 1 (mirroring) and the performance of RAID 0 (Stripping without parity). The disadvantage of RAID 10 is that it offers just 50% of the size of the physical disks that make up the array.
RAID 50 and RAID 10 Compared
In the last part of this tutorial, I will compare RAID 50 and RAID 10. I will summarize the benefits offered by each. The section will also highlight the drawbacks of each RAID type.
|S/N||Features||RAID 50||RAID 10|
|1||Data Redundancy||RAID 50 offers better redundancy as it combines striping with parity and stripping without parity.||RAID 10 offers Some level of redundancy as it combines mirroring and striping without parity|
|2||Performance (Speed)||This RAID combination delivers faster read and write||This RAID configuration is slow to write but may offer the same read as RAID 50|
|3||Storage Space Offered||RAID 50 will give you more storage volume compared to RAID 10||This RAID configuration will deliver less storage volume as it requires two disks to write the same data.|
|4||Cost||RAID 50 requires very complex controller to implement. It also requires a minimum of 6 disks. This makes it considerably more expensive to implement.||In comparison to RAID 50, RAID 10 requires just 4 disks to configure.|
|5||Data Recover||Recovery from failure is slow because RAID 5 need to calculate parity information to rebuild the failed array. Though recovery will depend on where the disk failure occurs. If multiple disks from the same RAID 5 set fails, recovery may be impossible||In a RAID 10 array, sets of mirrored disks are stripped. Data recovery is possible depending on which drive fails. If multiple disks fails in the same mirror set, the volume is irrecoverable|
There you have it – RAID 50 vs RAID 10 compared. I hope the tutorial helped you improve your understanding of RAID.
I will appreciate your sincere feedback. Kindly use the “Leave a Reply” form at the end of the tutorial to let me know what you think. You could also share your knowledge so other readers can benefit from it.