Solved

Failed Raid 1 Mirror.

I used 2 3 TB hard drives to create a Raid 1 Mirror using Windows 10. Worked fine for several months the I got a Mirror Failed message. I cannot read data from either drive. How do I recover?
12 answers Last reply Best Answer
More about failed raid mirror
  1. Restoring from your backups is the best, fastest, and easiest way. Raid is not a backup in any of its forms.
    That being said:
    How was the raid created? Software/windows raid, motherbd raid (amd or intel)? or Via Raid Controller card (which one?)?
    What was the complete error message? They usually give an indication of which drive(s) has failed.
    Have you tried replacing the failed drive and letting the mirror rebuild?
    How are you trying to read the drives? Many raid controllers use a linux format that is not native to windows and cannot be read without additional software.
  2. popatim said:
    Restoring from your backups is the best, fastest, and easiest way. Raid is not a backup in any of its forms.
    That being said:
    How was the raid created? Software/windows raid, motherbd raid (amd or intel)? or Via Raid Controller card (which one?)?
    What was the complete error message? They usually give an indication of which drive(s) has failed.
    Have you tried replacing the failed drive and letting the mirror rebuild?
    How are you trying to read the drives? Many raid controllers use a linux format that is not native to windows and cannot be read without additional software.
  3. I read redundant to mean a backup -- I think that is the intent. Thew raid was created using the Windows disk utilities. The message simply said Mirror Failed. Both disks are apparently still good according to windows. The have a different status according to Disk Management. One has a red triangle next to it and is Dynamic and Foreign, the other is Basic and Online but unformatted. I have not disconnected or reconnected any hardware. I am trying to read them simply by double-clicking. I need to recover this data. Are there special tools available?
  4. Redundancy means uptime, in case of drive failure the system stays up & running. Raid 0 being a special case which offers speed but no redundancy.

    Since windows 10 Home does not have a "Mirror" function and judging by your description it appears you used raid 0 or stripped and not raid 1 and you will need raid recovery software. If there is to be any chance of recovery the failed disk needs to actually be in good working condition because half of every byte of data is stored on it (the other half of the byte is on the other disk).

    Run the trial version of Zero Assumption Recovery just to see if it can detect the drives and let you know if there is some data to recover. There are other free tools that can work if data is recoverable; testdisk and linux's mdadm are the two I use. Neither of these are simple windows point and click so I like to start people with zar to see if its even worth going further.

    ps - I will not be on tomorrow.
  5. popatim said:
    Redundancy means uptime, in case of drive failure the system stays up & running. Raid 0 being a special case which offers speed but no redundancy.

    Since windows 10 Home does not have a "Mirror" function and judging by your description it appears you used raid 0 or stripped and not raid 1 and you will need raid recovery software. If there is to be any chance of recovery the failed disk needs to actually be in good working condition because half of every byte of data is stored on it (the other half of the byte is on the other disk).

    Run the trial version of Zero Assumption Recovery just to see if it can detect the drives and let you know if there is some data to recover. There are other free tools that can work if data is recoverable; testdisk and linux's mdadm are the two I use. Neither of these are simple windows point and click so I like to start people with zar to see if its even worth going further.

    ps - I will not be on tomorrow.
  6. I used Windows 10 professional and it did have a mirror function. Thanks for your help.
  7. You need to find the instruction manual for the Windows RAID utility that you are using. Within it, you need to read the section on RAID1. Virtually all RAID1 management software includes a set of tools to deal with failure of the array. Normally they will include tools to help you identify which of the two physical drive units has experienced an error and what type of error that is. Often they include a tool to "break" the RAID1 array so that it becomes just two separate HDD units with identical copies of the data. However, one of those units will have error problems, and one should be perfectly good. In that configuration, you should still be able to boot from the one good drive.

    Now you need to determine what error is on the failed unit and how to fix that. It may be a simple thing you can fix, or it may be that you have to replace that HDD completely. If you do have to replace, make sure it is as similar as possible to the good drive that is still running - identical if possible. When you have that repaired original or replacement unit re-installed, then the RAID1 utility also should have a tool to Rebuild the array by adding that new HDD to the array and copying ALL of the data from the old still-good drive to the new one. When the process is done, your RAID1 array will be back in operation.

    To be SURE you have all the tools you need and know how to use them, get that manual and READ it carefully.
  8. orestgogosha said:
    I used Windows 10 professional and it did have a mirror function. Thanks for your help.


    That's good news then!
    By any chance did you try ZAR to see what it finds?
  9. Paperdoc said:
    You need to find the instruction manual for the Windows RAID utility that you are using. Within it, you need to read the section on RAID1. Virtually all RAID1 management software includes a set of tools to deal with failure of the array. Normally they will include tools to help you identify which of the two physical drive units has experienced an error and what type of error that is. Often they include a tool to "break" the RAID1 array so that it becomes just two separate HDD units with identical copies of the data. However, one of those units will have error problems, and one should be perfectly good. In that configuration, you should still be able to boot from the one good drive.

    Now you need to determine what error is on the failed unit and how to fix that. It may be a simple thing you can fix, or it may be that you have to replace that HDD completely. If you do have to replace, make sure it is as similar as possible to the good drive that is still running - identical if possible. When you have that repaired original or replacement unit re-installed, then the RAID1 utility also should have a tool to Rebuild the array by adding that new HDD to the array and copying ALL of the data from the old still-good drive to the new one. When the process is done, your RAID1 array will be back in operation.

    To be SURE you have all the tools you need and know how to use them, get that manual and READ it carefully.
  10. Do you know if the manual is online? Would Microsoft Tech Support help? Thanks again for sticking with me on this.
  11. Best answer
    I found this page that seems to answer most questions. It appears to apply to most recent versions of Windows, although it does not specifically refer to Win 10. The work is all done within Disk Management and Device Manager. I assume from your earlier posts that this RAID array was NOT your boot device, and was used only for data storage / retrieval.

    https://technet.microsoft.com/en-us/library/cc938519.aspx

    From your posts it is possible that all that is wrong is that the two HDD units somehow have some different data on them, but each is still OK as far as disk functions is concerned. IF that is the case, you might succeed by a relatively short procedure. It appears the sequence would be:

    1. See "Replacing a Failed Mirror". After Step 2 the failed unit will contain no old data and be all Unallocated Space. Now treat that unit as a "new" HDD device that can be used for this repair. Use Step 3 to Add this back into the array. Back out of Disk Management and reboot.

    2. See the section "Resynchronizing Mirrored Volumes". Your system may simply detect the changes and do the resynchronizing step for you, and that will take a lot of time to copy all the data. Go into Disk Management to see what it is doing and follow progress. If it appears NOT to be doing that job by itself, you may need to tell it to do that with the Resynchronize Mirror command. When it is finished, back out of Disk Management and reboot to see if all is well.

    If that procedure does not do the job, there may be a more extended process necessary. Particularly, if the failed HDD actually has any serious errors in it and must be replaced, the procedure is different.
  12. Thanks for Best Solution. I hope it works out for you.
Ask a new question

Read More

NAS / RAID Hard Drives Mirror