Swap behaviour on Hw ssd raid

[tiberius]

Dear all,

Since the beginning of my Proxmox time I was curious about the swap behaviour especially with non zfs setups because I really do not really get it.
I tried to change the default 60 to 5 as well as also to 0 but it seems to have no effect at all (screenshot).
swapoff -a and sysctl vm.swappiness=0 follwed by swapon -a

Does it have something to do with ksm sharing / Balloooning which I use on my guests ?

All guest are configured / calculated to not overprovisioning the host (ram).
In my case, Is it recommended to disable swap at all via swapoff -a for perf. and lifetime reasons of my ssds ?

I hope that somebody is able to clarify this - BEst & greets!

 

[Alwin]

Swap is always used. I hope the article below can bring some insight.
https://chrisdown.name/2018/01/02/in-defence-of-swap.html

 

[tiberius]

Swap is always used. I hope the article below can bring some insight.
https://chrisdown.name/2018/01/02/in-defence-of-swap.html

Ok. thx!
So the recommended setting is the leve it untoueched=60 ?

 

[Alwin]

That's the default setting. Adjusting the value depends upon the hardware and workload running on it.

 

[tiberius]

That's the default setting. Adjusting the value depends upon the hardware and workload running on it.

This brings me back to my first post, I changed it to diferent settings(eg 5) but I does not seem to have an effekt......

 

[Alwin]

This brings me back to my first post, I changed it to diferent settings(eg 5) but I does not seem to have an effekt......

Then can I ask, did you read the article?

When talking about vm.swappiness, an extremely important change to consider from recent(ish) times is this change to vmscan by Satoru Moriya in 2012, which changes the way that vm.swappiness = 0 is handled quite significantly.

The link points to the commit explaining that setting swappiness to 0 will not prevent swapping. It just makes it least aggressive but it will still swap if needed. And in general swap is a good thing but sometimes needs some tuning.