How to expand the storage array on a DSSRV.


Discharge all static electricity from your person by touching metal prior to handling any hardware. Failure to do so may result in damage to devices.


The steps detailed in the resolution of this article may result in a loss of critical data if not performed properly. Before beginning these steps, make sure all important data is backed up in the event of data loss. If you are unsure, please contact Product Support Services prior to attempting the procedure below.


The storage array needs to be configured for a new drive.

Product Line

Pelco Video Management


  • RAID5


The storage array does not expand automatically when additional storage is added.



Management of the RAID controller on the LSI 9750-8i RAID controller card in the DSSRV is performed using the tw_cli command line utility.  Tw_cli allows direct execution of commands or may be used in interactive mode.  Tw_cli must be executed by an administrator. 

  1. Open a Windows Command prompt with administrator privileges:
    1. Select the Start button and type cmd in the search box.
    2. In the search results right-click on the cmd.exe file.
    3. Select Run as Administrator.
    4. If prompted by UAC, click Yes to proceed.
  2. In the command window type:  tw_cli and then press [ENTER]. The prompt will now change to a //<computernameprompt.  Example: //PC-AFKTG35>
  3. Type /c0 show [ENTER] to show and verify the units status. The Status should have a value of OK       

    The output of the /c0 show command provides more detail of the c0 controller and displays the status of all configured units.  The lower portion shows the connected drives and their unit membership.  This is the primary way to view the health of the DSSRV RAID5 storage array.
  4. Insert the new disk into the next available drive slot.  Allow the new drive a few moments to initialize before proceeding.

    Note:  Disk status LED will not display when drive is inserted.
  5. Show the controller status. By using /c0 show [ENTER]
  6. If the unit number is shown as a dash ' - ' then the drive is likely brand new, skip to Step 8.
  7. If the unit number is shown as “u?” or “u1”, the drive has likely been used in another array and will need additional steps to prepare the drive for use.

    1. To remove a drive with an unidentified Unit id “u?”or 'u1,2,3..etc' unit status, enter commands:
      1. At the tw_cli prompt type the following command replacing c0 and p3 with the correct controller and port numbers:

        maint remove c0 p3 (p# = port number new disk is using) [ENTER]

      2. When the command completes, issue the following command to redetect the drive:

        maint rescan [ENTER]

      3. /c0 show [ENTER]
      4. The new drive is now seen by the controller as “u1” and details of the RAID5 array it was once a member of are shown.
        1. Delete the invalid unit by issuing the command:

          /c0/u1 del [ENTER]  Type 'Y' when prompted "Do you want to continue ? Y:N)

        2. The /c0 show command should display all drives in a state similar to below:

        3. Verify the new disk displays a ' - ' for the unit.

  8. Issue the migrate command to add the new disk to the array.

    For the DSSRV models: /c0/u0 migrate type=raid5 stripe=64 disk=3 (disk=# matching port number for new disk)
    For the DSSRV2 models: /c0/u0 migrate type=raid5 stripe=256 disk=3

  9. Monitor the progress using the /c0/u0 show command.

    In the example above “su” indicates the source unit and “du” the destination unit for the migration. 

    To check the status of the migration, look for the percentage complete under %V / I / M

    Note: The migration process can take a very long time (2 or more days to complete), allow the process to complete before proceeding.  The process can be made to complete faster by changing the rebuild rate at the expense of performance. Default = 1 slowest.
    Use the command  /c0 set rebuildrate=5  (where 5 is the selected value [1=slowest 3=middle/balanced 5=fastest]) to change the rebuild rate and speed up the migration.
  10. After the migration is complete and the Status = OK, reboot the DSSRV.
    1. Open the Windows Computer Management console (Start > Right-Click Computer and select Manage.)
    2. Expand Storage and select Disk Management.

    3. Right-click on the partition which shares the same disk as the Unallocated space (Example.  D:\ volume above.)
      In the right-click menu, select Extend Volume...
      Note: If you get an error "The volume cannot be extended because the number of clusters will exceed the maximum number of clusters supporeted by the file system." 

    4. The Extend Volume wizard opens to an introductory page, click Next.
    5. When the Select Disks screen appears, confirm that the correct disk was automatically selected and that the space allocation is set to maximum space in MB.

    6. Click Next, then click Finish to commit the change.
    7. Within a few moments the volume will resize.  Verify the total space available on the volume.

    8. Reboot the DSSRV.
    9. Check the size of the storage location is correctly reported in DS Admin.