Raid5 problem

Posted on 2007-07-25
Last Modified: 2013-12-23
I have 3 physical drives with Raid5 setup, two drives are 74gb, and one is 9gb, however, after installing the Win2k I get only 16GB on a C drive, and I dont see other space available at all.  I have only one array A created and wont allow me to create array B.  How would I create an arrayB?  I want C and D drive, but I am unable to allocate space for D drive.  Windows allowed me only to use 17gb upon installation.  Where did the other drives go ? and how can I use them for a D drive?

Thanks in advance.
Question by:Rohail2004
    LVL 95

    Accepted Solution

    A RAID 5 volume will be equal to the size of the smallest disk multiplied by the number of disks and subtract the size of the smallest disk.  So in this case, 9 GB is your smallest disk - 9 x 3 disks - 9 (the smallest Disk) = 18 GB (in raw terms; actual size will vary because of file system overhead and the way manufacturers market the drives).

    So, in short, your RAID is performing EXACTLY as expected with the disks you have.

    As for how to use the other 65 GB on each drive, you would need to create another array in the RAID controller's BIOS.  How you do that depends on the RAID controller - and I HAVE seen some RAID controllers that simply do not permit multiple volumes on a disk.

    I would suggest you replace the 9 GB drive with another 74 GB drive and reinstall.

    Author Comment

    Thanks,  I will follow your advice and try to reinstall.

    Appreciated... I am new in Raid stuff..

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