I manage a VPS based on Ubuntu 18.04 server and I was surprised that there are less than 200Mo of SWAP for 4Go RAM, and all swap memory seems used (Swap usage: 100% at ssh login)
After searches, I found answers like 62073, useful for desktop/personal ubuntu, but not for server in data-center.
Must I increase swap size on my server?
The administrator explained me that it is important to notice than it could be a lot of VM (40 in my case) on real server machine, so the right way is to avoid lock disk space, but set correctly the required RAM.
The red hat advice at : https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/storage_administration_guide/ch-swapspace mentioned in How to decide on Swap size post explain their point of view if "you want sufficient memory for your system to hibernate". In my case, the server never hibernates (data center), so no much Swap memory.