I would like to increase harddrive space on Dell T320 - PERC 310, currently has four 1 TB hotswap drives, Raid 5, four drive bays available. Configured as one array with (3 partitions?) a C: drive 500GB, E: 1.5TB, F: 1TB.
I see the steps to physically add the HD and configure with OMSA.
While we normally don't address software issues, it would really be down to the OS you're using. If Windows Server 2016 or newer you can go to Disk Management and use the Volume Extend function. If using 2012 or older then you would need to use a tool like Extpart.