9 Replies Latest reply on Oct 3, 2015 12:57 PM by joe_intel

    RAID 5 Configuration


      Hi folks,


      My understanding of RST is (as will quickly become apparent) pretty limited.  I'm not even sure what question to ask.  Here's what's going on. 


      I've configured a RAID 5 array using RST on 3 1TB disks (932GB actually, I'm rounding).  I expected to see 2TB of usable storage.


      When I look at the array with RST, under Manage Volume the type is shown as RAID5 and the size is says 2TB  Under Storage System View all three drives are shown and the size is also shown as 2TB. 


      That is exactly what I expected, but when I look at the drive in Windows Explorer (Windows 10) it shows the size as 1TB.


      Can anybody help me understand why they don't agree?




        -  Dick


      PS - If I've posted this in the wrong place or otherwise broken any rules, I apologize.  Please let me know.

        • 1. Re: RAID 5 Configuration

          Update.  I figured out why I was seeing different sizes and it was simple.  When I created the RAID array it created 2TB of usable space but allocated 1TB as drive C and left another 1TB as unallocated.  Kind of a Duh! moment, but at least I'm learning.


          I'd like to get this all to be usable as a single 2TB volume, drive C. 


          I couldn't find anything in the manual that would help me and the only reference to what I want to do that I can find in the Help in RST says to go to Windows Disk Management and extend the volume.  However that option in Disk Management is grayed out.


          I'm guessing way to do this would be to update my latest backup, start over and recreate the array from scratch with no data, and then restore.


          If anyone could give me any advice on how to proceed or hints on where to find more definitive information I'd really appreciate it.




            -  Dick

          • 2. Re: RAID 5 Configuration

            Is this the boot volume? You may need to use GPT instead of MBR-based partitioning.

            • 3. Re: RAID 5 Configuration

              Thank you, joe-intel.  I appreciate the response.  I which I knew what it meant.  :-)  GPT and MBR are not things I've encountered before.  I will do some homework.


              It is the boot volume BTW.  It's not obvious to me that either Windows Disk Management or RST gives me the answer the info re GPT vs. MBR.  I'll try to dig a bit though.


              Thanks again,


                -  Dick

              • 4. Re: RAID 5 Configuration
                Cesar Badilla



                Please take into consideration that in order for an operating system to fully support storage devices that have capacities that exceed 2 terabytes (2 TB's), the device must be initialized by using the GUID partition table (GPT) * partitioning scheme.

                Additionally if you intend to start the computer from one of these large disks, the system’s base firmware interface must use the Unified Extensible Firmware Interface (UEFI) * and not BIOS.


                Caesar B

                • 5. Re: RAID 5 Configuration

                  Thank you, Cesar.  I'm clearly well over my head in this but I'll do my best to figure it out.  (This all because HP claims the system it sold me is supported except for RST, although after 3 weeks they still cannot show me any documentation which excludes RST (or anything else for that matter).  I'm quite frustrated (other phrases come to mind) with HP.)  I really do appreciate that folks here are trying to guide me.


                  BTW, the drives are only 1TB.  It's the combined RAID5 volume of 3x1TB that would yield 2TB usable.  Nothing usable exceeds 2TB. 


                  Does what you suggest still apply in that case?

                  • 6. Re: RAID 5 Configuration
                    Cesar Badilla

                    Hello dduggan47


                    In this particular case, as the whole volume will be 2TB's it is preferable to have a GPT partition set up in UEFI in order to ensure best performance and compatibility with your system.




                    Caesar B.

                    • 7. Re: RAID 5 Configuration

                      Thanks, Cesar.  You have no idea how much I appreciate your help (and also that from Joe-intel). 


                      I have determined that my my drive (actually the set of 3 drives seen by Windows as 1) is UEFI/GPT. 


                      So ... since what I want to do is combine the two 1TB partitions into a single 2TB I'm guessing that I had the right strategy initially, "... update my latest backup, start over and recreate the array from scratch with no data, and then restore".


                      Thanks yet again.


                        -  Dick

                      • 8. Re: RAID 5 Configuration
                        Cesar Badilla



                        We are glad to be of assistance.


                        Best regards,

                        Caesar B.

                        • 9. Re: RAID 5 Configuration

                          I hope you have succeeded.

                          I am sorry for coming back late, I just wanted to include these links in case they are needed: