Hi Mohammed,
It's going to work for iSCSI as you are simply mounting existing VMFS Volume (the raw disk is formatted and created as VMFS).
Unmounting won't work, I've tried this myself in the past to see if this could be tested. Eventually, I had to setup a test mirror.
I used the script above to migrate some virtual machines + DR situation, I don't see a problem with it.
I think a test mirror should be setup, no matter how the script is written, even like a 1GB of mirrored disk should be fine!
-Steven