What to do if we have multiple disk types attached in a CentOS7 VM?

Question

I would like to ask for your expertise on how to create one single partition disk from two disks

Currently, my main disk is 'sda' where my machine is running the second disk is mounted and used for backups only The Third Disk (NEW) is attached on the VM as is named 'nvme0n1'

This third and new disk is exactly the same brand and model as the main one with the only difference that at the moment of creating the VM I set up the disk as whole physical disk and formatted for Linux only (don't know if this info is relevant, but is here now)

I wonder if is possible to create a combination of the disk 1 (sda) and 3 (nvme0n1) as one disk only?

What could be the best approach without losing all the data here? if wonder, Can I attach a Fourth disk for Full VM Backup and do a complete format of both disk and then create something like a RAID 0 with both NVME disk (1&3) and then pass all over?

Any suggestion and procedure will be kindly appreciated. Thanks!

NAME                    MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda                       8:0    0 465.8G  0 disk 
├─sda1                    8:1    0   500M  0 part /boot
└─sda2                    8:2    0 465.3G  0 part /
sdb                       8:16   0     1T  0 disk 
└─sdb1                    8:17   0  1024G  0 part 
  └─vgBackup2-lvBackup2 253:0    0  1024G  0 lvm  /home/user/backup
sr0                      11:0    1  1024M  0 rom  
nvme0n1                 259:0    0   400G  0 disk 
└─nvme0n1p1             259:1    0   400G  0 part 

Answer 1

I managed to solve my issue.

Steps from anyone interested in the Future:

I decided to create a backup of the current machine disk /SDA

Then I followed the steps provided in this blog here

I test the new .vmdk file to make sure works os the original, Deleted the disk previously mentioned. Created a RAID 0 for the two nvme's and created a Daily task for VM backup in case of any failure in the future to be able to restore the machine with new disks or simply to recreate the VM with more disk for a better RAID Solution.