[SOLVED] Swap and drive implementation question

Krupski · 05-28-2022, 10:43 AM

Hi all. If this is the wrong forum, mods please move and my apologies.

Ok, my over 10 year old machine died and had to build a new one. This new one has 128GB of memory (yes, DRAM, not HDD). Started with 64GB, but the two empty UDIMM slots bugged me... had to fill them!

Anyway, my swap questions are: (please provide explanation for answers):

Do I even need swap since there's so much ram?
If yes, what size should it be? RAM*2?
Should I make any change to "vm.swappiness"?
My "hard drives" are two 2TB SATA3 SSD devices.
Planning to install a small, fast (~250 GB PCIE-4 NVME) drive solely for swap. Good idea, or no?

My thinking is that using a dedicated device for swap keeps R/W wear off the main drives.

BTW, if it matters, the OS is 64 bit Debian 11.3.

Any info will be appreciated. Thanks!

pan64 · 05-28-2022, 10:53 AM

ok, there are actually three pages you can read:
the first one: how memory handling works: www.linuxatemyram.com
the second is exactly the answer to your question: https://chrisdown.name/2018/01/02/in...e-of-swap.html
about the size: https://opensource.com/article/18/9/...-linux-systems

jailbait · 05-28-2022, 12:18 PM

Quote:

Originally Posted by Krupski

[1]Do I even need swap since there's so much ram?
[2]If yes, what size should it be? RAM*2?
[3]Should I make any change to "vm.swappiness"?
[4]My "hard drives" are two 2TB SATA3 SSD devices.
[5]Planning to install a small, fast (~250 GB PCIE-4 NVME) drive solely for swap. Good idea, or no?

My thinking is that using a dedicated device for swap keeps R/W wear off the main drives.

1. You don't need any swap unless you plan to use hibernate.

2. If you use hibernate then you need a swap area the same size as your ram.

3. It depends on your configuration. From what you have shown here I think that vm.swappiness is irrelevant to you.

5. Your swap partition will be unused. Use your SSD for something that will be very active.

Krupski · 05-29-2022, 05:39 PM

Quote:

Originally Posted by pan64

ok, there are actually three pages you can read:
the first one: how memory handling works: www.linuxatemyram.com
the second is exactly the answer to your question: https://chrisdown.name/2018/01/02/in...e-of-swap.html
about the size: https://opensource.com/article/18/9/...-linux-systems

Those links cleared up a lot of swap misconception. Thanks! Thread solved.