What is RAID 0?
RAID 0, also known as disk striping, is a type of RAID configuration that splits data evenly across two or more disks without parity information. The main benefit of RAID 0 is improved performance, as data can be written and read in parallel across multiple disks. However, RAID 0 provides no redundancy or fault tolerance, so if one disk fails, all data will be lost.
Can you convert a RAID 0 array to a non-RAID configuration?
Yes, it is possible to undo a RAID 0 array and convert the disks back to standalone non-RAID disks, restoring them to the state before the RAID 0 array was created. Here is an overview of the process:
Back up any important data
Before making any changes to the RAID 0 array, it is essential to back up any important data stored on the array. As soon as the array is broken, all data on the array will be lost if it is not backed up elsewhere.
Delete the RAID 0 array
Using disk management software or the RAID configuration utility in the system BIOS, delete the RAID 0 array. This will revert the disks to non-RAID disks. The data will still be present but the disks will no longer be striped together in a RAID array.
Partition and format the disks
Once the RAID array is deleted, the disks will show up as raw unallocated space. They will need to be manually partitioned and formatted, just like new blank hard drives. Create the desired partitions on each disk and format them as needed for the intended use, such as NTFS for Windows or HFS+ for Mac OS.
Recover data from backups
With the disks now formatted as standalone non-RAID disks, copy back any important data that was backed up before breaking the RAID 0 array. With the disks no longer in a RAID configuration, the data will be accessible as normal.
Can you convert a RAID 0 array to a RAID 1 mirrored array?
Converting from RAID 0 to RAID 1 is possible in some cases but comes with limitations:
Add disks to match capacity
To convert RAID 0 to RAID 1, enough disks must be added to match the total storage capacity of the RAID 0 array. For example, two 1TB disks in RAID 0 would require adding two more 1TB disks to convert to a four disk RAID 1 array.
Back up data and create new RAID 1 array
After adding the matching disks, all data from the RAID 0 array must be backed up. Then the RAID 0 array can be deleted, and a new RAID 1 array can be created using all of the disks. Data can then be restored to the new array.
Data will need to be fully copied over
The limitation is that a direct conversion is not possible. The data will need to be fully backed up, the RAID 0 array deleted, and an entirely new RAID 1 array created. This can mean lengthy copy times for large amounts of data.
RAID 1 array will only be as large as smallest disk
In addition, the RAID 1 array will only be as large as the smallest disk. So if the two 1TB RAID 0 disks are combined with two 2TB disks to create the RAID 1 array, total capacity will be 2TB instead of 4TB. For full expanded capacity, all disks must be identical sizes.
Can data be recovered after deleting a RAID 0 array?
Unfortunately, no. When a RAID 0 array is deleted, the data spread across the disks is irrecoverable without extensive specialized expertise:
Data is split across disks
In RAID 0, data is split and written in segments across multiple disks with no parity or duplication. The benefit is fast read/write speeds. The downside is there is no built-in redundancy.
No redundancy means data cannot be rebuilt
With the RAID 0 array deleted, the standalone disks contain only fragments of the original data with no information on how those fragments map back to files. There is no redundancy that would allow the missing data to be rebuilt.
Requires manual recovery of each disk
Highly skilled data recovery specialists may be able to manually scan the disks, identify fragments of files, and attempt to reconstruct the original data. This is a very complex, expensive, and unreliable process. Most users do not have access to such expertise.
Best to rely on backups, not RAID 0 recovery
The only reliable method of recovering data from a deleted RAID 0 array is to restore from a backup. For this reason it is absolutely critical to maintain current backups of a RAID 0 array. Relying on attempting to undo RAID 0 as a recovery method after failure or deletion is generally futile.
Steps to completely undo a RAID 0 array
Here are the detailed steps to safely convert RAID 0 disks back to standalone non-RAID disks:
1. Back up all data
Ensure you have full backups of everything stored on the RAID 0 array. This data will be deleted when the array is broken, so backups are mandatory.
2. Delete the RAID 0 array
Using disk management software like Disk Utility on Mac or Disk Management on Windows, delete the RAID 0 array. This will revert the disks to standalone mode.
3. Clean the disks
Use diskpart on Windows or dd on Linux to completely wipe and erase each disk if needed, ensuring no RAID configuration data remains.
4. Create new partitions
Use the disk management software to create new partitions on each disk as desired. Format the partitions for use.
5. Restore data from backups
With partitions formatted on the newly standalone disks, restore data to each disk from the backups taken before deleting the RAID 0 array.
6. Validate disk health
Check SMART status and run disk verification tools to ensure the newly independent disks are fully healthy and functional.
Following this process will safely undo the RAID 0 array and restore the disks to standalone non-RAID configuration without data loss.
Reasons you may want to undo a RAID 0 array
There are a few scenarios where undoing RAID 0 may be desirable:
Transitioning to a backup-focused redundancy strategy
Some users choose to switch from the performance focus of RAID 0 to a backup-based redundancy plan for greater flexibility. Undoing RAID 0 enables implementing this revised strategy.
Increasing storage capacity
With RAID 0, storage capacity equals the smallest disk times the number of disks. By undoing RAID 0, all disks become individually addressable for increased storage potential.
Changing physical disk configurations
If hardware needs to be replaced or the physical disk configuration needs altering, undoing the RAID 0 arrays allows greater flexibility to change disk models, sizes, etc.
Increasing portability
Standalone disks are easier to connect to different systems than hardware RAID 0 arrays. Undoing RAID 0 improves portability.
Reducing disk failure impacts
RAID 0 has no redundancy so a single disk failure results in total data loss. Undoing RAID 0 decentralizes data so a single disk failure only impacts a portion of the data.
Reasons you may NOT want to undo a RAID 0 array
There are also scenarios where undoing RAID 0 may be undesirable:
Decreased performance
RAID 0 provides significant performance benefits from simultaneous disk access. Undoing it reverts back to the slower speeds of individual disks.
Data recovery difficulties
As covered earlier, reliable data recovery after deleting a RAID 0 array is nearly impossible in most cases. The data protection of RAID 0 should not be depended upon.
Existing hardware dependencies
Some RAID 0 implementations are hardware-based. The disks may not be removable from the RAID enclosure, complicating the process of undoing the array.
Complexity of data migration
The backup and restoration steps needed to safely migrate data off a RAID 0 array can be time consuming and complex for extremely large data sets.
Loss of RAID management features
RAID 0 arrays provide monitoring, configuration and other management conveniences that will no longer be available after undoing the array.
Risks when undoing a RAID 0 array
While undoing a RAID 0 array is possible, there are notable risks involved:
Accidental data deletion
If backups are incomplete or improper procedures are followed, permanently losing data is almost inevitable when disassembling the array.
RAID configuration loss
If RAID metadata is not fully wiped from disks, trying to recreate the same or other RAID arrays can be problematic.
Physical disk damage
If disks sustain physical damage when removed from a RAID enclosure, recovering data becomes impossible.
Failed disk replacement
If disks in the original RAID 0 array are replaced or upgraded during the transition, existing data could be overwritten.
Array size limitations
Very large arrays take substantial time to back up and restore. Undoing the array may not be feasible within downtime constraints.
Proper procedures can mitigate these risks, but undoing any RAID 0 array requires careful planning and execution to avoid permanent data loss.
Best practices when undoing a software RAID 0 array
For software-based RAID 0 arrays, these best practices help smooth the transition to standalone disks:
Use reputable tools
Rely on well-known, stable RAID management software to delete arrays and partition disks. Avoid bootleg or unverified tools.
Follow vendor instructions
Closely follow all guidance from the storage vendor and RAID management software providers for supported steps to safely undo the array.
Wipe RAID metadata
Use disk wiping utilities like diskpart or dd to overwrite the first and last megabytes of each disk to eliminate residual RAID configuration data.
Match partition schemes
When partitioning disks after undoing the array, mirror the partition table and sizes from the RAID 0 configuration as closely as possible.
Verify restored data integrity
After data is copied back to standalone disks, spot check files for completeness and run checksums if applicable to validate successful restoration.
Best practices when undoing a hardware RAID 0 array
Hardware RAID 0 arrays present unique challenges. These tips help avoid issues:
Consult hardware vendor documentation
Hardware vendor manuals will provide the only authoritative process for properly deleting the array in their RAID device. Follow their guidelines explicitly.
Ensure disk removability
Some hardware RAID enclosures do not support removing disks. Verify disks can be taken out before attempting to undo the array.
Use identical replacement disks
When moving disks to a new enclosure, replacement disks should match the original models exactly to avoid size mismatches.
Retain RAID controller
If possible, connect the disks to the original RAID controller temporarily to delete the array before moving them to new enclosures.
Check for hardware limitations
Hardware RAID cards may not support partitioning disks after undoing the array; required functionality may be limited.
Frequently asked questions about undoing RAID 0 arrays
Here are answers to some common questions about undoing RAID 0 configurations:
Can I simply remove the disks from a RAID 0 array without deleting it?
No, this will likely result in data corruption or loss. The proper procedure is to delete the array first before physically removing the disks.
What happens if I create a new partition on the disks without wiping them first?
Leftover RAID metadata may interfere with repartitioning if the disks are not wiped correctly after the array deletion.
Do I have to format the disks again after undoing RAID 0?
Yes, partitions will need to be created and filesystems like NTFS or ext4 will need to be reapplied after the array transition.
How can I tell if RAID data is still present after wiping the disks?
Use RAID management software to check for metadata remnants, or look for configuration data at the start or end of the disks using a disk editor.
Is it possible to undo RAID 0 without losing data?
No, data loss is guaranteed without backups. The only way to reliably preserve data is backing it up before transitioning away from RAID 0.
Summary
While RAID 0 provides increased performance, it lacks redundancy. If the goal is data protection, converting RAID 0 arrays back to standalone disks can facilitate backup-based strategies. With proper precautions, RAID 0 arrays can be successfully undone, but data loss is inevitable if reliable backups are not taken beforehand. Carefully following the detailed steps outlined above will allow smoothly transitioning away from RAID 0 to standalone disks when the benefits no longer outweigh the risks.