I liked the server I set up the other day. 512 gigs of ram, 1 gig swap.
We’re using maybe 100gigs currently.
Why even bother having swap at that point?
Because it’s not what what you think it is and doesn’t do what you think it does. https://chrisdown.name/2018/01/02/in-defence-of-swap.html
Disabling swap does not prevent disk I/O from becoming a problem under memory contention, it simply shifts the disk I/O thrashing from anonymous pages to file pages
While the rest of that post matches my understanding of swap (I still think 1GB is next to useless in this case), that summarized point perplexes me.
What non-special file(s) does the kernel write to and read from, and how does it know how much space to use?
That’d be over 1TB with zram on
This comment is how I learned about zram. Just one question, when is it used?
Yep. I just looked it up.
I assumed it was like windows page file but it’s ramdisk.
Fedora enables it on all systems with <4GB (maybe a bit less I forget). It’s trivial to enable/disable it and see if its helpful for your usage.
Depends on config, ArchWiki recommends optmizing some sysctl values to take advantage of it
it generally starts kicking in after >60% RAM usage even with this config
Me watching my kernel shove 16gb worth of in use virtual memory into zswap in a desperate attempt to run 20 heavy applications on 8gb of physical memory