RAID (Redundant Array of Independent Disks) is a data storage technology that combines multiple disk drive components into a logical unit. The main purposes of RAID are to provide data redundancy, improve performance, or both (Source 1). When using RAID with two drives, the two main options are RAID 0 and RAID 1.
RAID 0 stripes data across the two drives, providing improved performance but no redundancy. RAID 1 mirrors the data between the two drives, providing redundancy but no performance gain (Source 2). This article explores the pros and cons of each RAID level when using two disk drives, and provides recommendations on which to choose.
What is RAID 0?
RAID 0, also known as disk striping, stripes data across both drives to increase performance (TechTarget, 2022). This means it breaks up data into blocks and spreads the blocks across multiple hard disks or solid state drives in the array. By spreading data across multiple disks, RAID 0 enables faster reads and writes compared to a single disk (PCMag, 2022). However, RAID 0 offers no redundancy if a drive fails, meaning if one drive fails, all data across both drives will be lost (The Plug, 2020).
What is RAID 1?
RAID 1, also known as disk mirroring, mirrors data between two drives to provide redundancy in case one of the drives fails (https://www.techtarget.com/searchstorage/definition/disk-mirroring). This RAID configuration writes identical data to both drives simultaneously so that if one drive fails, the data remains intact and accessible on the second drive.
RAID 1 essentially makes an exact copy of your data on the second drive, protecting your data against drive failure. If one drive fails, you can replace it and rebuild the RAID 1 array without any data loss (https://www.pcmag.com/encyclopedia/term/raid-1). The drawback is that you effectively only get the total capacity of one drive, as the second drive mirrors the first. But RAID 1 remains a popular option for increasing fault tolerance and uptime for storage systems.
RAID 0 Pros
One of the main advantages of RAID 0 is faster read and write speeds [1]. By striping data across multiple disks, RAID 0 allows for simultaneous disk access which improves performance. For example, striping data across two hard disks would provide nearly double the read and write speeds compared to a single disk.
Another advantage of RAID 0 is that the full storage capacity of all disks is usable [2]. If two 1TB drives are configured in RAID 0, the total usable space would be 2TB. This makes RAID 0 ideal for setups that require both speed and storage capacity.
RAID 0 Cons
The biggest disadvantage of RAID 0 is that it offers no fault tolerance. Since the data is striped across multiple disks with no parity or mirroring, the failure of just one drive will result in complete data loss for the entire array (1). If any one of the drives fails in a RAID 0 setup, all data across all disks will be lost. There is no protection or redundancy. This makes RAID 0 a risky choice for mission critical or highly important data.
According to TechTarget, “The disadvantage of disk striping is low resiliency. RAID 0 does not use data redundancy, so the failure of any physical drive in the striped disk set results in data loss across the entire set” (2).
RAID 1 Pros
One of the key advantages of RAID 1 is its fault tolerance. Since the data is mirrored between the two drives, if one drive fails, the data remains intact and accessible on the other drive [1]. This provides protection against data loss due to hardware failure and makes RAID 1 a highly reliable solution.
In addition, recovering data is straightforward with RAID 1. If a drive fails, you simply replace it with a new, blank drive which will be automatically synced to the existing drive, rebuilding the mirror. The rebuild process is also relatively quick since no parity calculations are required [2].
RAID 1 Cons
One of the main disadvantages of RAID 1 is that it offers slower performance compared to RAID 0 [1]. This is because with RAID 1, all data is written to both disks simultaneously. So for every write operation, there are two disk writes instead of just one. This doubles the I/O utilization and can result in slower write speeds.
RAID 1 also has the disadvantage that only 50% of the total storage capacity can be used [2]. Since the data is mirrored between the two disks, the total usable space is equal to just one disk. For example, with two 1 TB drives in a RAID 1 configuration, the total usable space is 1 TB, not 2 TB.
So in summary, the two main cons of RAID 1 are slower write performance compared to RAID 0, and only 50% usable storage capacity.
Recommendations
When choosing between RAID 0 and RAID 1 with two drives, it mainly comes down to whether reliability or maximum performance is more important for your needs:
RAID 0 offers the highest performance, but no redundancy. Data is striped across both drives for faster reads and writes. However, if one drive fails, all data will be lost. RAID 0 is best for non-critical data where speed is the priority. RAID level 0, 1, 5, 6 and 10 | Advantage, disadvantage, use
RAID 1 provides redundancy through disk mirroring, but at the cost of storage capacity. Both drives contain identical copies of the data, so if one drive fails, data is still accessible from the other. However, performance will be slower compared to RAID 0. RAID 1 is recommended for critical data where reliability is more important than maximum speed. Selecting the Best RAID Level
In summary, RAID 0 is best for performance, while RAID 1 is best for reliability. Consider how critical your data is and whether downtime in the event of a disk failure is acceptable. Weigh the pros and cons of speed vs. redundancy to determine which RAID level makes the most sense for your specific needs.
Setting Up RAID
The general steps to set up RAID in Windows 10 are:
- Open the Settings app and go to the System tab.
- Click on Storage and then select Disk Management.
- Right-click the unallocated space on your disks and select New Mirrored Volume to setup RAID 1 or New Striped Volume for RAID 0.
- Follow the onscreen prompts to setup the RAID array.
- Choose your physical disks to include in the array.
- Specify the RAID level and volume size.
- Windows will format and initialize the RAID array.
You can also manage and configure RAID through your BIOS/UEFI settings on bootup. The steps can vary depending on your specific motherboard and chipset, but generally involve:
- Entering BIOS setup by pressing a key like Delete or F2 during boot.
- Navigating to the RAID configuration options.
- Choosing to create a new RAID array.
- Selecting the RAID level and assigning physical drives.
- Saving changes and rebooting.
The BIOS method allows configuring RAID before the OS loads for better performance. Refer to your motherboard manual for detailed steps.
Conclusion
Based on the key differences outlined through comparisons between RAID 0 and 1, choosing the right setup for your 2 drive system comes down to your priorities and use case.
If you need maximum storage capacity and don’t mind some risk, RAID 0 combines your two drives into one large volume for storing data. Just be aware that if one drive fails, all data will be lost. RAID 0 is best for non-critical data.
On the other hand, RAID 1 mirrors your two drives to protectively store the same data twice. Performance may be slower but you gain fault tolerance – if a single drive fails, data integrity is maintained. RAID 1 is ideal for critical data you cannot afford to lose.
Carefully weigh the pros and cons of speed, capacity, and redundancy. Analyze your storage needs and risk tolerance. With two drives, RAID 0 provides speed and space while RAID 1 focuses on safety and reliability. Choose the right balance for your priorities.