If I use ASM, and define a +DATA group with say about 10 partitions of 450Gb, I have a 4.5Tb. If disk usage is smaller (due to the smaller tablespaces), I can simply remove one or two partitions, and let ASM balance. If the partitions are removed, I can use fdisk linux commands to remove them.
Instead 10 partition in one (1) Lun of 4.5TB, create 10 Luns of 450GB each and one partition per Lun.
As you plan use only 2TB in the future I recommend you create LUN of 200GB each, this way you can save more space.
Using 200GB of LUN you don't need wait free 450GB to remove the Lun. In each 200GB you can free or add more 200GB as needed.
My questions and doubts.
Is it possible to create so many disk partitions in Linux. What are the pittfalls I should look for?
How to remove a disk the right way (what are all the steps needed for ASM and linux commands)?
Follow step in documentation.
Would the storage engineer be able to identify the disk that has to be removed. How?
Skill and knowledge is needed on OS and Storage S/W.
You will need a SA.
I suppose you have this documented. right?
Thanks for your comments.
After some playing around with Virtualbox, I found out many steps. One thing remains: If I delete partition /dev/sdg1, how can we find which disk can be removed from the host (in this case virtualbox client). I guess that is only fixable by keeping a good documentation. Right?