This looks more like the menu for compacting free space rather than compacting globals. Compacting free space is a bit less IO intensive and probably a more viable option given the amount of Disk Free indicated. After free space is compacted it can be returned to the file system by truncating the database.

Going forward, i'd make a practice of keeping the directories that you want to operate cache in owned by the cache user (cacheusr) and the group. Also, doing a ccontrol start as root will typically provide permissions that these issues won't come up. Root is especially useful later when record locking comes into play

I'm guessing it is a permissions issue. I would start by opening the directory up 

chmod 777 /home/centos

Better yet, are you starting caché as the root user? That might help considerably

Yes, not sure why I was assuming windows.

You can get the status of the ISCAgent by running

systemctl status ISCAgent.service

(on each instance - look for "Active (running)" ) - more about how to manage this on *nix from this link

https://docs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KEY...

I think Robert Cemper hit the nail on the head. ISCAgent is a service in Windows, make sure it is running on both the primary and the asyncs/Failover members.