this post was submitted on 19 May 2026
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I have been setting up Zram, Swap, Swappiness and EasyOOM daemon on 16gb ram boxes, or lower. Someone asked me about 32gb of ram, or more, and I'm unsure. Wondering if others have experimented with this!

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[–] HelloRoot@lemy.lol 18 points 1 month ago (1 children)
[–] kiol@discuss.online 5 points 1 month ago (1 children)
[–] mactan@lemmy.ml 3 points 1 month ago

been testing this quite a lot for star citizen which regularly sees 20-40 GB use. zram is the easiest solution to avoiding OOM Killer by a long shot. zswap was swapping over 100 GB to disk cumulative throughout the day and still oom killing the game

[–] Heavybell@lemmy.world 3 points 1 month ago

Yeah, I have 96gb and I still assign a zram swap, just in case. I also have a zram tmp, and a zram for my portage compilation dir (I use Gentoo). The latter gets the most use.

[–] PetteriPano@lemmy.world 2 points 1 month ago* (last edited 1 month ago) (1 children)

zram makes sense if you do not have swap.

zswap is probably enabled by default in most distros. It compresses cold pages on the fly so that they're ready to quickly get swapped in and out.

I do hit the swap partition occasionally on my 32GB systems.

It doesn't really kick in until you have proper pressure. I want my swap partition for hibernation, anyway.

[–] monovergent@lemmy.ml 1 points 1 month ago (2 children)

My workstation has 48 GB RAM with 50% allocation allowed to zram, no swap. It works just fine. Once I use up the majority of my RAM, it kicks in the same way it would on any other system with less RAM.

[–] motruck@lemmy.zip 2 points 1 month ago (1 children)

Not according to the chrisdown blog post above.

[–] monovergent@lemmy.ml 0 points 1 month ago (1 children)

What about it? I see it kicking in at least 10 GB before my RAM is full and I haven't noticed any fundamental differences between how zram works on my 48 GB workstation and my 8 GB devices. Maybe I've never had a workload that filled all 48 GB + extra zram capacity, but it's never given me an issue.

[–] motruck@lemmy.zip 2 points 1 month ago

Use zswap not zram.

[–] SoulKaribou@lemmy.ml 1 points 1 month ago (2 children)

Shouldn't total ram amount always be powers of 2 (forgot the reason exactly) ? It sounds like 32 +16 wouldn't be ideal ? I remember that from my early days, but maybe it has changed ?

[–] FleetwoodLinux@lemmy.zip 3 points 1 month ago

There are some 24GB sticks around, same with 48GB sticks

[–] monovergent@lemmy.ml 1 points 1 month ago

That is correct, IIRC, the mismatch does limit how much of it can run in dual-channel. Even if a single stick is natively 24 or 48 GB, there is additional strain on the memory controller. It is the way it is on my setup since I had planned an upgrade to a full 64 GB and was holding off until a good deal on the remaining 32 GB kit, which will never come unless the AI bubble bursts.

[–] Eggymatrix@sh.itjust.works -1 points 1 month ago (3 children)

Genuinely curious: what are you doing to be needing this?

I cannot think of any modern usecase for swap a part from hybernation

[–] kiol@discuss.online 5 points 1 month ago

I've been using lower ram machines lately, so made me curious about if people are using things like zram with 32gb+

[–] amorangi@lemmy.nz 5 points 1 month ago (1 children)

Local AI can chew it up. Wasn't able to run certain jobs on 64Gb until I switched to zswap.

[–] Eggymatrix@sh.itjust.works 1 points 1 month ago

What kind of token per second are you getting with your model partially on disk?

[–] Outsider9042@lemmy.world 2 points 1 month ago (1 children)

Compiling Librewollf with a sufficient number of jobs is a great way to eat up 32GB of RAM, and the some.

[–] Eggymatrix@sh.itjust.works 0 points 1 month ago (1 children)

Swapping will make it slower not faster, reduce jobs?

[–] Outsider9042@lemmy.world 0 points 1 month ago (1 children)

No. Most of the build jobs are fast and small. A couple take up gigabytes at a time. Swap is on SSD anyway. Its fast enough.

I also use NixOS and GuixSD. There are cases where binary caches haven't caught up with the package definition. Situations like Librewolf, LibreOffice and kernel all compiling at the same time.

Sure I could mess around with limiting jobs and build runners... Or I could just have swap, and never worry about it again.

Just a BTRFS swapfile. I'm not worried too much about performance. I rarely hit it and most of the time i don't even need it. Until I do.

[–] Eggymatrix@sh.itjust.works 1 points 1 month ago

Ok, you do you. In my experience that is not how that works, but there is an argument to not worry about it if it works well enough.

[–] ISO@lemmy.zip -2 points 1 month ago (3 children)

Why do you think 32GiB is special compared to 16GiB?
And wtf is EasyOOM?

You maximize the usefulness of zram by actually increasing sappiness, and giving zram devices high priority. e.g.

sysctl vm.swappiness=100

for i in {1..8}; do
  swapon /dev/zram${i} -p 32767
done

Then you enable other swap devices with lower priority.

This is the way regardless of how much RAM you have. I mean, it may be pointless if you never ever exceed, let's say 10/32GiB (including caching). But it still wouldn't be harmful in any way.

[–] non_burglar@lemmy.world 5 points 1 month ago* (last edited 1 month ago) (1 children)

That isn't how swappiness works.

Changing the sysctl for swappiness only adjusts the ratio of anonymous and file pages, it doesn't set a "threshold" or "aggressivity" in swapping pages, nor does it dictate how much or how little to swap.

It's generally ill-advised to touch swappiness at all unless you know what you're doing. You can start here.

If you're going to hand out free advice, at least make sure the advice is worth the price of admission.

[–] ISO@lemmy.zip -5 points 1 month ago (1 children)

If you’re going to hand out free advice, at least make sure the advice is worth the price of admission.

This is very ironic, considering your comment is a mix of straw man and wrong.

[–] floquant@lemmy.dbzer0.com 3 points 1 month ago

"a strawman is when people disagree with me!"

[–] kiol@discuss.online 2 points 1 month ago

I simply haven't had the chance to try it yet, so asking

[–] kiol@discuss.online 1 points 1 month ago (1 children)
[–] ISO@lemmy.zip -3 points 1 month ago

Oh, you wrote "easy" not "early" in OP. In any case, this looks stupid. But to each their own, I guess.