Kubuntu 26.04 LTS - important things to do after an installation

[Virginio Miranda]

Well, yes I don't use it as a server. The way I use this laptop is mainly for desktop activity, mainly AI graphics and desktop graphics, intense use of browsers, quite some movement of files but mainly on external disks to avoid stressing the Samsung SSD 512Gb (28% used space). I use it during the day and log out the session for the night every day. I didn't know that swapping is essential to hibernation but in my case hibernation is not essential, I can as well shut down if the use of Zram is better for my case than Zswap, no big issue. My main disk I/O is not that crazy though, because I avoid stressing or filling it up. When it was almost full under Windows it started to dysfunction so I learned from that too. I have 32 Gb of Ram, a RTX Nvidia 3050 graphic card, on a Dell G15 with 12x 11th gen. I5 cores. Sometimes under intense use and other times not so much. This can give an idea of what could be the best strategy, but anyway, I'll read those links. The chrisdown.name site though receives an unusual quite dissuasive warning of Firefox that I've never seen before so I'll have to skip it. What I wonder is that since Zswap swaps the files that are difficult to compress or handle, then Zram I guess may have sometimes digestion issues, since it compresses everything regardless of fat or calories, but it seems to get better over time with high fat carnivore diet. The advantage for me of either Zram or Zswap for me would not be about a lack of Ram but rather to help in cases of intense use of software I guess. Graphical AI apps seem make intense use of Vram, CPU, Ram and Swapping as seen in my system monitor. Another advantage that is mentioned is that even if Zswap uses swap it greatly reduces its amount if I understood correctly.

Since you have decided to skip to read the chrisdown page above, you are not able to understand in a better way the swap mechanism. You are doing some kind of confusion. And now with the Zram and Zswap the things get to be worst.

My suggestion: follow the OP suggestion and leave the swappiness=10. If it does not work for you change for 60. That is all.

[JoshiFresa]

Since you have decided to skip to read the chrisdown page above, you are not able to understand in a better way the swap mechanism. You are doing some kind of confusion. And now with the Zram and Zswap the things get to be worst.
My suggestion: follow the OP suggestion and leave the swappiness=10. If it does not work for you change for 60. That is all.

The page was "not safe" to browse but I find a way around it and read it. So yes, zswap is the way to go for me and that's what I'll be trying to install. On some distros it's installed by default but in my case I will have to use command line to do so. I know you want to avoid me getting into trouble and also learn more before doing something stupid. Thanks for that. If you have any advice to install zswap, thanks in advance. There's a guide in the Chris Down review but it's always good to be well prepared for possible issues.

My swap file is quite small, that I installed when I installed Kubuntu. You suggested 32 Gb for a swap file previously in my case.

 free -h
               total        used        free      shared  buff/cache   available
Mem:            31Gi       5.9Gi        17Gi       651Mi       7.9Gi        25Gi
Swap:          511Mi       460Mi        51Mi
  ​

I found this old post. What do you think of this straightforward approach, beyond the fact of it messing up with the grub file?

https://www.reddit.com/r/linux/comme...ting_up_zswap/

[Snowhog]

AI Overview

Deciding on swap size for a modern Ubuntu installation depends primarily on two factors: your total RAM and whether you need hibernation support.

For general use cases (no hibernation), follow these baseline tiers:

• Less than 2 GB RAM: 2x your RAM size (e.g., 1 GB RAM = 2 GB swap).
• 2 GB to 8 GB RAM: Equal to your RAM size.
• 8 GB to 16 GB RAM: 4 GB of swap is typically sufficient for balanced paging.
• More than 16 GB RAM: 2 GB to 4 GB is often enough unless you have specific memory-intensive needs.

Crucial Decision Factors

• Hibernation: If you want to use the "Hibernate" feature (suspending to disk), your swap must be at least the size of your RAM plus a small margin (typically round√(RAM) additional space) to hold the entire system state.
• SSD Wear: On modern Solid State Drives (SSDs), frequent swapping can slightly increase wear, though modern controllers manage this well. Using a smaller swap or lower Swappiness (e.g., 10–20) can reduce disk writes.
• Out-of-Memory (OOM) Protection: Swap acts as a safety net. Even with large RAM, having a small (2–4 GB) swap file prevents the system from immediately crashing if you hit a sudden memory spike.

Swap File vs. Partition

• Swap File (Default): Recommended for most users. It lives inside your existing root partition and can be resized instantly using standard terminal commands.
• Swap Partition: Historically slightly faster, but modern kernels and SSDs have made the performance difference negligible. Use this only if your filesystem (like Btrfs without specific configurations) doesn't support swap files well.

To check your current usage and decide if you need more, run free -h or swapon --show in your terminal.

[Trinity-108]

what about zram-generator use or zram-tools. it may be helpful ?? i had only 8gb ram..currenly set up zram-genenrator and setup by gemini .


[zram0]

zram-size = ram / 2

compression-algorithm = zstd

swap-priority = 100
i need your opinion..isthis ok to continue to use as it is and swapiness=80 ..

[Virginio Miranda]

The page was "not safe" to browse but I find a way around it and read it. So yes, zswap is the way to go for me and that's what I'll be trying to install. On some distros it's installed by default but in my case I will have to use command line to do so. I know you want to avoid me getting into trouble and also learn more before doing something stupid. Thanks for that. If you have any advice to install zswap, thanks in advance. There's a guide in the Chris Down review but it's always good to be well prepared for possible issues.

My swap file is quite small, that I installed when I installed Kubuntu. You suggested 32 Gb for a swap file previously in my case.

 free -h
total used free shared buff/cache available
Mem: 31Gi 5.9Gi 17Gi 651Mi 7.9Gi 25Gi
Swap: 511Mi 460Mi 51Mi
​

I found this old post. What do you think of this straightforward approach, beyond the fact of it messing up with the grub file?

https://www.reddit.com/r/linux/comme...ting_up_zswap/

Hi there,
I suggested 32 GB of swap size only for test purpose and hibernation in case a lot of usage.
Zram is not for you, not for me and probably not for most of the desktop usage. Imagine what happens when zram fill out of space.
And what about zswap? Maybe yes, maybe not. For your specific case i can not see no advantage using it.

Since you brought us a snapshot of your memomy usage ( free -h ), we can do some suggestion:

Almost sure your swap is a swapfile and not a swap partition. Kubuntu use as a default a swapfile of 512 Mi with 32 GB of ram memory.
You have a 32 GB of physical memory ram.
Your swap usage is a little, but almost using up all the space in the swapfile.

Look at that link from reddit that you posted.

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash zswap.enabled=1 zswap.compressor=lz4 zswap.max_pool_percent=50 zswap.zpool=z3fold"

Can you see zswap.max_pool_percent=50 ?

With zswap you need to setup some parameters and the pool size is one of them. The number of 50 mean you are going to create a size of a half of your 32 GB memory ram space. But for what? For a performance? What a waste of precious RAM space using only 460 Mi of swap. Right, lets try 20 then, maybe 10...again...for what?

You might be thinking about SSD wear and tear, but that's in the past. Modern SSDs are much more reliable and can handle far more read and write operations than their older counterparts. You have specifics tools for monitoring the lifespam of this devices from the manufacturer.

Now, we have to think about the others parameters too. Compressors. Zswap needs to compress and decompress the swap in e out. Look at the zswap. compressor and z3fold choice. Your CPU usage will arise. And...again...for what? A usage of 460 Mi of swap?

It does not make a sense for you to setup zswap on your system. Your memory ram device can handle in the better way than using a zswap.

Back to your memory usage snapshot:

You have 25 Gi of available memory ram. 17 Gi are free, but we have to remember that the kernel use this memory as a cache and free here does not mean entirely free.

In other words, you have a lot of ram memory still avaiable to the system.

I have to say too that your swappiness is setting to 60. It seems it. Anyway you have to check it .

So, in your case you have two opions that does not compromise your precious memory ram and CPU process :

1- Enlarge your swapfile space for at least 1 Gi and keen an eye on it. Leave swappiness as 60. ( I would try these first option first. )

2- Enlarge your swap file for 1 Gi and Use e a choice of 10 for your swappiness. Follow the OP suggestions and see how the system perform .



And for last, do not forget that you'll need to setup a swapfile space on your SSD or on a Hard Disk device in the same amount of your zpool space in ram if you decided to use zswap.

In time: remember to check that default or discard option that OP said in his fiist post.

[Virginio Miranda]

what about zram-generator use or zram-tools. it may be helpful ?? i had only 8gb ram..currenly set up zram-genenrator and setup by gemini .


[zram0]

zram-size = ram / 2

compression-algorithm = zstd

swap-priority = 100
i need your opinion..isthis ok to continue to use as it is and swapiness=80 ..

Look at the post above. You can be a candidate for use zswap option instead, but you have to monitorate if you really need this.

[Schwarzer Kater]

Wow.
Coming back here after some time (I had to switch my internet connection from VDSL to optical fiber which took longer than expected…) I have to say that this did turn into an informative discussion without going down too far "into the rabbit hole" IMHO (as claydoh had put it).

As many things in Linux (and computing as such) there is no solution that is best for everyone and my "important things to do after an installation" are meant as suggestions based on my experiences and knowledge aquired over the years - and are not rules carved in stone.

[…]
My suggestion: follow the OP suggestion and leave the swappiness=10. If it does not work for you change for 60. […]

I cannot agree more. Try out what works best for you if you have the time.

[smith]

X11 is install but I don't see it at the bottom left of the login screen.

[Snowhog]

IF you have X11 installed, then on the SDDM Login Screen, the bottom left will show Desktop Session: Plasma (Wayland)

You just have to mouse-click on that to bring up the options.

[Schwarzer Kater]

To make this clearer, the explanation has been expanded accordingy.