Replace swap partition with zram-generator

[septatrix]

Swap partitions (and files) can result in many writes to slow disks, reduce their lifespan, and claim disk space* not usable by other means. Zram-generator solves this problem but still keeps swap for better handling of OOMs and for compressing rarely used pages. Due to the advantages Fedora for example has also made it the default years ago: Changes/SwapOnZRAM.

ParticleOS should follow best practices and adopt zram instead of a swap partition

*This is especially true because its repart definition has 4G as the minimum and it is not set to optional. So trying particleOS in a VM, one has to reverse 4 additional gigs of space

PS: Only advantage of a swap partition to my knowledge is support for hibernate but as far as I am aware this doesn't work for Secureboot or encrypted partitions anyhow?

[poettering]

I am not convinced. Swap is good. It lowers pressure on the disk because seldom used memory can be written out to disk. It's usually much worse to avoid swap and thus increase paging pressure because the pool of reclaimable memory is so much smaller.

That said, I a fine with a swap hierarchy. i.e. install zram with some higher priority than on disk swapping.

[septatrix]

For servers with lots of services I can see the appeal of disk-backed swap as there are likely many pages that will pretty much never be accessed again. For desktops though this is often a way smaller share. File access is more random and apps are not as long lived.

To my knowledge the Fedora steering committee did some experiments back then and noticed that zram is generally better for interactive scenarios than disk-backed swap. If you have low ram/swap utilization zram has no disadvantage. If you have very high ram/swap utilization disk-backed swap often leads to lower system responsiveness. The area where zram would fare worse in theory (the point where ram+swap usage is such that the zram region contests with the uncompressed ram region) does not seem that impactful because even if more swapping has to be done it is quicker than a few swaps to disks. Yes the OOM killer might kick in a bit sooner but even that is rarely observed and the drawback of sizing the zram a bit larger is not that huge