10 Replies Latest reply on Dec 21, 2009 10:21 AM by tariely

    srombsasfc raid controller raid 5 drive group. why do I show free space?

    jawz101

      I have a raid controller configuration consisting of 5 drives:

      drive group 0-Raid1:

      virtual drive size 135.973 GB consisting of 2 147GB drives

       

      drive group 1-Raid5:

      virtual drive size 135.973 GB consisting of 3 147GB drives

      135.973 GB free space

       

      drive group 2-Raid1:

      virtual drive size135.973 GB consisting of 2 147GB drives

       


      .... my question is, while i don't know how the drive group 1 is only using 136GB drive space, how can I get that virtual drive in the drive group to use it?

       

      attached is a screenshot in raid web console

        • 1. Re: srombsasfc raid controller raid 5 drive group. why do I show free space?
          edwardzh

          This is more of how the drive capacity is calculated. Normally HDD manufacturers will use 1KB = 1000B, 1MB = 1000KB, and 1GB = 1000 MB. However, operating system and RAID web console will use 1KB = 1024B, 1MB = 1024KB, and 1GB = 1024MB. So in your case, you 147GB hard drive's capacity is actually 147,000,000,000 Bytes. OS and RAID web console will calculate it as 147,000,000,000/1024^3 = 136.9GB.

           

          Also in RAID web console there is an option called "Drive Coercion". Drive coercion refers to the ability of the controller to recognize the size of the physical drives connected and then force the lager drives to use only the amount of space available on the smallest drive. Drive coercion allows an option to map out a reserved space to compesate for slightly smaller drive sizes that may be added later. The default is set to 1GB.

           

          So the RAID controller has already used all your drive spaces, exept for the 1GB reserved by Drive Coercion.

          • 2. Re: srombsasfc raid controller raid 5 drive group. why do I show free space?
            jawz101

            3 147GB drives at RAID level 5 should be an array size of approx. 293.97GB and a usable size of 273.78GB.  My question is if there is a way to reclaim the free space that somehow the array halved.

             

            I'm not expecting full usage of the three 147GB drives.  I'm expecting 273.78GB of usable size which, somehow I have 1/2 of it designated as within the array.

            Please see the screenshot.

            • 3. Re: srombsasfc raid controller raid 5 drive group. why do I show free space?
              edwardzh

              I see... Sorry for the misunderstanding.

              You can run configuration wizard in BIOS console or web console to add a second virtual disk to use the free space.

              • 4. Re: srombsasfc raid controller raid 5 drive group. why do I show free space?
                jawz101

                Thanks.  I figured I needed to clarify.

                I guess I was hoping that I could somehow resize my virtual drive to consume the remaining space that the RAID5 had offered.  It seems peculiar that it would have only picked up a portion of the space.

                My only option I see right now is to copy the data off of the virtual drive, remove and recreate the virtual drive within the drive group & move the data back on.

                My concern is if it simply reoccurs and gives me the same halved space after recreating the virtual drive.  I'm just scrutinizing the process before I jump into it.  Didn't know if there was some sort of higher level operation in the web console that could claim additional space, as it were.

                • 5. Re: srombsasfc raid controller raid 5 drive group. why do I show free space?
                  edwardzh

                  The RAID controller doesn't have a function to resize a virtual drive. However, you may try the steps below. But before doing it please backup all your data.

                   

                  1. Once you have all your data backed up, reboot the system and press Ctrl-G to launch RAID BIOS console.

                  2. Select Configuration Wizard => New Configuration

                  3. Select Custom Configuration

                  4. Select hard drives and proceed with RAID configuration. Make sure you select same hard drives as your previous configuration.

                  5. In the VD Definition step, make sure RAID Level and Strip Size is same as your previous configuration.

                    • Note the Select Size field in the bottom of the page. Here is the reason why you have only half capacity: for a 3-drive configuration, the default RAID level is RAID 6. When you change it to RAID 5, you'll need to input VD size here to use all the spaces. There is a notice on the right of the window telling you the possible size of each RAID level, but you'll need to change it manually. Below is a screenshot:

                       

                      RBC.jpg

                  6. Proceed with VD creation.

                  7. Important: when you're asked "Want to Initialize?" select No. Do NOT initialize the VD otherwise all your data will be gone.

                  8. Complete the wizard and reboot your server.

                   

                  If everything goes well you should be able to load the OS and get all your data. If not you may need to re-install OS and restore data from backup.

                  • 6. Re: srombsasfc raid controller raid 5 drive group. why do I show free space?
                    edwardzh

                    Hello,

                     

                    I took a look at your screenshot again and notice that you have more than one VD configured, so the procedure should be a little different:

                     

                    After you launch the RAID BIOS console first delete VD1.

                    In step 2, Do NOT select New Configuration. Instead, select Add Configuration. Then follow steps 3~8 to create a VD without initialization.

                     

                    If your OS is not installed on this VD you may also do it in RAID web console.

                    • 7. Re: srombsasfc raid controller raid 5 drive group. why do I show free space?
                      jawz101

                      Thanks.  I knew an answer was going to take me into a pit of despair

                      • 8. Re: srombsasfc raid controller raid 5 drive group. why do I show free space?
                        jawz101

                        Ideally I think I can do it through the web console as it doesn't hold the OS.

                        I'm going to back up all of the drive groups, then go to the web console & drive group 1 & 2 to get around 440GB out of a RAID5 array.

                        Regardless of the end result I figured it would be a step-through process.

                         

                        Here's the steps I plan to take:

                        -image drive group 0

                        -copy drive group 1 & 2 to a backup drive

                        - verify all of the backups

                         

                        - log into raid web console & delete drive groups 1 & 2, click controller icon & add a virtual drive group using free space (from drives I just removed) at raid 5.

                        - once initialized copy my data back onto this new raid.

                        -verify the data

                         

                        btw, you're awesome for fielding these questions.  I'm a cautious person on this

                        • 9. Re: srombsasfc raid controller raid 5 drive group. why do I show free space?
                          jawz101

                          Thank you Thank you Thank you

                          You saved me a lot of headache.  I finally did my maintenance on the server this weekend (after a bunch more planning) and it was painless.

                           

                          Thank you again for your help and attentiveness.  You don't know how much of a sigh of relief that was.  I've had a few fires with this database server that I've had to put out, so to speak.  It's holding a 90GB medical record system and I wanted to measure twice and cut once before I did this maintenance work.

                           

                          The drive group with that pesky slack space is now a whopping 277GB and now I have the breathing room I need.

                           

                          Thank you so much for your help.  and thank you for looking at that attachment.  It was one of those 'pictures worth a thousand words' things