Intel Software Raid: Downgrade from RAID10 to RAID 1

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My configuration

My target

  • I want to remove 2 of the HDDs permanently from the RAID because I don’t need that much space anymore. The Raid should be RAID 1 afterwards (mirroring)
  • None of the discs is faulty.
  • I don’t want to re-install Windows 8.1, obviously.

My question

  • What do I have to do to downgrade this RAID10 to RAID1, such that I will be able to remove 2 of the 4 HDDs afterwards?


You aren’t going to be able to just “switch” RAID modes like that, as the array would need to be recreated/reinitialized.


  • Reduce data so it’s small enough to fit on the RAID1.
  • Get an external drive that’s large enough to accommodate your data (and then some).
  • Perform full system backup to external drive.
  • Destroy RAID10.
  • Remove 2 drives.
  • Create RAID1.
  • Restore Backup from external.

If you can’t obtain an external drive (aka: “slow, nitpicky, dangerous way”):

  • Reduce data so it’s small enough to fit on the RAID1.
  • Determine which drives (by serial number, etc.) are in which part of the RAID10, and pull the two you can afford to loose (that won’t bring the array down).
  • Create an additional array that’s RAID1, using the two drives you detached from the RAID10.
  • Perform full system backup from degraded RAID10 to healthy RAID1.
  • Destroy RAID10.
  • Create RAID1 with two drives that were last in RAID10.
  • Restore Backup from first RAID1 you made.
  • Destroy RAID1 you first made.
  • Remove 2 drives.

Note: Have RAID controller drivers available on USB at all times.

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