Can one partition the main drive under RAID 1?

I have the 6TB WD Duo with RAID 1. I'd like to partition a 3TB drive but as soon as I partition it with Disk Utility, the hardware senses that there is a difference between the two drives and subsequently rebuilds the partitioned disk into a single 3TB disk.

Western Digital My Book Duo Thunderbolt RAID Hard Drive

Western Digital My Book Duo Thunderbolt RAID Hard Drive

Product No Longer Available

2 Answers from the Community

  • Answer

    Hi Erika,

    After some trial and error I finally did it. Open Disk Utility. You need to first erase the WD Thunderbolt Raid that is preconfigured. Then you go to the first 3TB WDC and create your partitions and name them. You then go to the second 3TB WDC and create the same size partitions and name them. After that, select the first partition and its RAID tab. I then dragged the two like partitions from each of the drives and named it - creating a RAID 1 drive. Then I did the same for the second partition and so forth. The end result is two (or multiple) drives of same size that are RAID1s.

    Hope that helps:)

  • Thanks for the answer Gil.

    Just to be absolutely clear, when I open Disk Utility now, I see three references to the Thunderbolt Drive. The first two are named "3TB WDC WD30...". Then our standard hard drive is listed followed by another reference to the drive, "3TB Our Thunderbolt Duo" where "Our Thunderbolt Duo" is what we named the drive. Each of the three references to the Thunderbolt drive has subheadings. You're saying ...

    (1) Delete the third reference named 3TB Our Thunderbolt Duo.
    (2) Partition the two 3TB WDC WD30... drives identically -- just for clarity, I'll call the drives A and B and each partition x and y such that each partition is Ax, Bx, Ay, and By.
    (3) Open DiskUtility and the entry for Ax.
    (4) Set the Bx as the RAID 1 slice for Ax and do the same for Ay and By.