Your disk layout is done using LVM it is a Logical Volume Manager, you can use it to dynamically change the layout of the partitions during system operation (resizing, creating new volumes, creating snapshots for backup etc.)
The lower part of what you have pasted show a home
LV that is 387GB long.
I suppose that when you type df -h
in CLI you will see that your total disk space sums to your disk size, but is dispersed among a few mountpoints and not allocated to only one of them.
the lsblk
command will also show you the layout in some more friendly way
You need to rethink on what layout would you like to have and perhaps it will be easier for you to reinstall the OS paying attention to the layout this time (centos 8 installer has a nice gui that allows you to adjust the layout during installation)
Shrinking the partitions now is a good practice if you are interested in Linux mor than just using it. But might be somewhat unfriendly.
LVM is managed through commands :
vgdisplay
- shows volume groups
lvdisplay
- shows logical volumes
lvcreate
- creates new volumes
resize2fs
- resizes filesystems so you can reduce partition size (can destroy data)
lvresize
- resizes volumes
lvremove
- removes logica volumes (deletes data)