Online Capacity Expansion

Well…

  • Call me old fashion…
  • Call me conservative…
  • Call me a doubting “Thomas”…
  • Call me tickled pink…
  • Call me surprised…

I just finished adding four additional spindles to one of my virtual hosts; when I originally built it out I only had four spindles available, and didn’t want to buy more since I knew I would be freeing up smaller spindles for it soon.

The first task was to have the RAID software add the new spindles to the array, then to “expand” the array container… the first step took only a few moments, the second step took about 20 hours for the array controller to rebuild / expand the array.

The second task was to get Windows to actually use the added space by expanding the volume; to do that was a simple matter of using diskpart.exe (you can search Microsoft’s Knowledge Base) only took a few moments.

The incredible thing about this was that my virtual host and virtual machines was online for the entire 20 hours — with absolutely no service interruption.

This particular machine used a Dell / LSI controller; but the Promise controllers also support dynamic capacity expansion as do 3Ware controllers.  I believe the Intel Matrix pseudo RAID controller also support dynamic capacity expansion; but as with other RAID and pseudo-RAID controllers you should check the documentation specific to it and consult the manufacturer’s web site for errata and updates before proceeding.

The bottom line is Windows and RAID arrays have come a long way, and it’s quite possible that you will be able to expand the capacity of your array without taking your server down; however, if the data on the server is irreplaceable, I recommend you consider backing it up (at least the irreplaceable data).

Originally posted 2008-12-01 12:00:56.