How to safely delete disk volumes on a RAID 5 logical disk in order to expand the C: volume?

Question

Our small office has a RAID 5 server with 4 2TB disks using HPE S100i software RAID, running windows server 2016. The office files are just in the Shared folder of the C: volume, but for some reason when the server was configured the C: volume was only allocated 500GB.

We're now running out of space on C: but obviously have several terabytes available. They're allocated in the D: volume (all page files, etc are on C:) which is mostly empty except some some empty folders and unimportant configuration files, but it contains around 30GB of files in the system volume information folder.

I'm not an IT administrator by any means but I have a working understanding of these things. I understand that I need to provide unallocated space directly adjacent to C: to extend the C: volume, which shrinking the D: volume does not do in the native windows disk manager.

From what I understand some paid 3rd party tools can shrink the volume from the "front" of the volume so that the newly unallocated space is adjacent to C:, but we are a small office, the 500GB is all files from the last 8 years or so and we should only need to do this once. Our disaster preparedness is also quite lacking so we do not have any local backups of the server.

I am going to acquire a 2tb external hard drive to backup the server fully before I do any of this, but my main questions are these:

1. Can I safely delete the D: volume and extend the C: drive into the unallocated space without messing up the RAID configuration or risking data loss?
2. Are the ~30GB of files in the System Volume Information folder on D: important to the RAID configuration or otherwise?
3. Should I just use a third party tool that claims to be able to do this without deleting any volumes? (eg. niubi partition editor). My main hesitation with that is the server-level versions of these software are quite expensive for what should be a one-time operation.

Any help would be much appreciated!

Thanks

Screenshot of the Disk Management Screen. Volume E: was created from volume D: while I was trying to figure this out, it is fully empty and can be modified.

Answer 1

Taking a total backup is a good idea before manipulating partitions. I recommend taking an image backup of the whole disk

The attempt to create E was unsuccessful, because that's not the way. You should have left E as unallocated, then used a third-party partition editor to move D down, which would have moved the unallocated space up and adjacent to C. Finally, boot Windows and resize C to incorporate that space.

For answers :

1. The RAID configuration is apart from the partition setup, so partition editing won't affect the RAID. You may delete D, although you aren't obliged to, as described above.

2. No.

3. A product that I like is the free AOMEI Backupper Freeware (but others exist). For disk backup, it will by default only backup used sectors from the disk, therefore speeding the backup process and reducing the size of the backup image. I also recommend to Create AOMEI Bootable CD/DVD/USB Based on Windows PE, to be able to restore a non-booting disk.