Hello,
If you currently have a linear vdisk (disk-group) you can use expansion to add additional drives in order to make the vdisk larger. However, be mindful that the vdisk size may grow to be larger than some OS versions support. If this happens you cannot remove the additional drives once they have been added using expansion. This would result in you not utilizing the additional capacity.
The other important point to consider is expansion can take a very long time to complete. If you lose a drive during the expansion you can also put your vdisk at risk. There is an old advisory for the P2000 Vdisk expansion. The general information in that advisory still applies to the MSA2040: https://support.hpe.com/hpsc/doc/public/display?docId=emr_na-c03034418
There is also some helpful troubleshooting information in the MSA Guided Troubleshooting that covers expansion: https://support.hpe.com/hpsc/doc/public/display?docId=c05177410
My suggestion would be if you want to increase the capacity of a vdisk (linear disk-group) I would backup the data, delete the old vdisk, create a new vdisk of the correct size, and restore all data. This process while offline would be quicker and safer.
Also, just in case you have not considered this, your current vdisk should be running scrub and have all the disks on current firmware versions if you are going to use the expansion utility.
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.