How to expand a LUN on your SCST Bauer-Power SAN

I thought I had already written about this, but apparently I haven't. Many moons ago I developed what I like to refer to as a Bauer-Power SAN. It was actually an idea I got from a former boss of mine named Craig MacKinder who is the current owner of Blueshift Information Systems. He had originally built similar SANs using Gentoo Linux. I think the only real difference between his and mine are that mine are built with Ubuntu.

Anyway, some people may not like these SANs because managing them is done purely via a Linux terminal, and there aren't any cool GUIs to help you with it. Because of that you need to know your way around a Linux terminal to manage one. If that isn't a big deal to you, then you can save tons of money by using these instead of something like a NetApp.

Anyway, the point of this post is to tell you how to add more space, or expand a LUN on your Bauer-Power SCST SAN. You can do it in these 5 easy steps!

• Create a temporary thin disk file the size of the amount you want to add to the LUN (For example 100 GB is 100G or 1 TB is 1T).
  dd if=/dev/zero of=temp_expand bs=1 count=0 seek=100G

• Append the temporary file to the end of your LUN file.
  cat temp_expand >> LUNFILE

• Once the partition is extended you can delete the temp_expand file you created.
  rm temp_expand

• Now to have scst recognize the change you must force the device to resync. You can get the device name of the file you are extending from /etc/scst.conf.
  scstadmin -resync_dev DEVICENAME

• Now you should see the additional storage on the partition you are trying to extend, and you can extend the partition. In Windows you need to open Disk Manager and rescan disks first. Then you can right click the drive and click extend.

See, that was pretty easy right?