Tuesday, September 28, 2010

How to Expand a Virtual Disk on the Dell MD3000i

I recently found myself in the position of having to expand a virtual disk on a Dell MD3000i. The Dell MD3000i is a great entry-point SAN, but the GUI lacks some of the functions that you think would be there (such as online volume growth).

The feat, however, can be accomplished. It just requires using the arcane command-line interface.

1. Log into the MDSM GUI and make sure no other operations are currently in progress (disk initialization, rebuild, etc). You can find this information on the Summary tab under Operations in Progress.
2. Note the virtual disk name that you want to expand (such as server_a_vol_1). To see a list of your virtual disks from the GUI, click on the Summary tab and then the Disk Groups & Virtual Disks link.
3. Note the name of the array. You can find this information on gray menu bar above the tabs.
4. Exit the MDSM GUI.
5. Open a command prompt and navigate to the directory where the MD storage software is installed (for the newer versions, the default location is C:\Program Files (x86)\Dell\MD Storage Manager\client on x64 platforms or C:\Program Files\Dell\MD Storage Manager\client on x86 platforms).
6. Run the command:

smcli -n arrayname -c "set virtualDisk [\"virtual disk name\"] addCapacity=n;"

arrayname is the name of the storage array
virtual disk name is the name of the virtual disk
n is the capacity in bytes to add (to convert GB to bytes, multiply the number in GB by 1073741824)

For example, if you want to add 50GB to the virtual disk server_a_vol_1 on the MD3000i array named production, you would type the following:

smcli -n production -c "set virtualDisk [\"server_a_vol_1\"] addCapacity=53687091200;"

From the Windows side, the LUN will not show up as its new size until the operation is complete. The volume growth process doesn't tack on space to the end of the volume, rather, it appears to move the volume to the end and then append the storage. For newly created volumes with no data, it is much faster to destroy the LUN and recreate it than to go through an online expansion. If the volume has data on it, though, you are left with little option.

Once the operation is complete, you can expand the volume using either the disk management snap-in (diskmgmt.msc) or diskpart.exe.

1 comment:

  1. Hi Aaron
    Is this something you offer as professional services, paid per hour? I have an MD3000i unit, where I need exactly the same thing done. Can I hire you?