Hello,
You can format the new drives while in production with no impact to current users. Just to clarify a little further. Whether you chose to use virtual or linear you will will create a disk-group on the array. You can chose an online option or an offline option. Chosing online lets you use the disk-group immediately from the host side. If you decide to chose the offline init all the parity and stripes need to be laid out before you can present to the host and allow host access. Either option is fine and neither will impact your current users. Online init offers immediate host access while offline means you have to wait. I personally use online init because it is faster.
Your plan for adding disk-groups and volumes looks good. A couple words of caution.
First recommendation is to take a full backup of all your data.
Be sure you have enough space on Vol0004 to fit all the current data in Vol003.
I would not expand volumes but delete and recreate. As long as your data is backed up this is quicker and provides you a more robust layout of your Pools.
Besure before you begin moving data and creating new disk-groups, that all your drives and the array are at the latest firmware versions.
A couple of guides you may be interested in.
SMU: https://support.hpe.com/hpsc/doc/public/display?docId=c04220794
MSA2040 Best Practices: https://h20195.www2.hpe.com/v2/GetPDF.aspx/4AA4-6892ENW.pdf
MSA and VMware vSphere Best Practices: https://h20195.www2.hpe.com/v2/getpdf.aspx/4aa4-7060enw.pdf
MSA Firmware & Release Notes: https://h41111.www4.hpe.com/storage/msafirmware.html
Good luck!
Cheers,
Shawn
I work for Hewlett Packard Enterprise. The comments in this post are my own and do not represent an official reply from HPE. No warranty or guarantees of any kind are expressed in my reply.