I am currently on Centos 7 and I am trying to free up some space on one of my disks so I can install Ubuntu along side of it (dual boot). I have a 2TB disk that is just under half full. This is not a primary disk, it is all backup. When I am booted into Centos the disk is
/dev/sdc, and is just a single partition (no numbers after
/dev/sdc). I created a bootable usb with Ubuntu 18.04 on it, booted from the usb, and the disk was recognized in that system as
/dev/sda. I ran gparted, and told it to shrink the partition by ~400GB:
This looked correct to me, so I went ahead and applied the changes. It finished without issue. However, when it was done there was still only 1 partition, with the unallocated space inside of it, rather than the partition itself shrinking. There's even an alert icon that when I click on it tells me that there is 390.63GB within the partition asking me if I want to grow it:
I know that I could, if I had enough disk space elsewhere, copy the data over and repartition this drive from scratch. However, I don't actually have enough space to do that, and things are pretty tight inside the box right now with 5 drives. Is there any way to split this drive into multiple partitions without going that route?
Not sure if this is relevant, but when I was still booted into Ubuntu the first time I did this I ran Check on it from gparted, and when it did that it automatically resized it back. I don't know if that means that it detected the wrong size as being an actual error, or if it is normal for gparted to just make use of extra space like that when you run check. I re-ran the resizing operation again before booting back into CentOS and it still currently looks like the second screenshot, and
df says that the partition is 1.5TB with 882GB used and 494G available.