Arch Linux

catastropeia

Member

Registered: 2016-12-05

Posts: 10

[SOLVED] Why is my swap space not used?

I just finished installing arch and everything seems to work fine. However, I just realised that my swap space, for which I allocated 16G during the installation process, is not used and I wonder why.

The partition layout of my arch installation (windows dualboot) is

├─sdb5            8:21   0   300G  0 part  
│ └─root        254:0    0   300G  0 crypt 
│   ├─main-root 254:1    0    80G  0 lvm   /
│   ├─main-swap 254:2    0    16G  0 lvm   
│   └─main-home 254:3    0   204G  0 lvm   /home

Running htop shows swap to be of size 0K:

  1  [|||                                                                              2.6%]   5  [||                                                                               1.3%]
  2  [|                                                                                0.7%]   6  [||                                                                               1.3%]
  3  [                                                                                 0.0%]   7  [|                                                                                0.7%]
  4  [|||||||                                                                          7.3%]   8  [                                                                                 0.0%]
  Mem[||||||||||||||||||||                                                      1.90G/15.4G]   Tasks: 44, 312 thr; 1 running
  Swp[                                                                                0K/0K]   Load average: 0.25 0.31 0.32 

I tried

sudo mkswap /dev/mapper/main-swap
sudo swapon /dev/mapper/main-swap

With the result that htop displayed the expected 16G swap space, however after reboot it was back to 0K.

Did I forget something in the installation process? Or is this normal under some circumstances?
Any hint is greatly appreciated.

Last edited by catastropeia (2018-12-02 15:05:46)

cloverskull

Member

Registered: 2018-09-30

Posts: 280

Re: [SOLVED] Why is my swap space not used?

Is it in /etc/fstab?

ngoonee

Forum Fellow

From: Between Thailand and Singapore

Registered: 2009-03-17

Posts: 7,362

Re: [SOLVED] Why is my swap space not used?

You have 16G of memory, of which less than 2G is used. Why should swap even come into the picture?

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Allan-Volunteer on the (topic being discussed) mailn lists. You never get the people who matters attention on the forums.
jasonwryan-Installing Arch is a measure of your literacy. Maintaining Arch is a measure of your diligence. Contributing to Arch is a measure of your competence.
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Slithery

Administrator

From: Norfolk, UK

Registered: 2013-12-01

Posts: 5,776

Re: [SOLVED] Why is my swap space not used?

Why on earth would you want your swap to be used instead of the shedloads of RAM you still have available?

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No, it didn't "fix" anything. It just shifted the brokeness one space to the right. - jasonwryan
Closing -- for deletion; Banning -- for muppetry. - jasonwryan

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catastropeia

Member

Registered: 2016-12-05

Posts: 10

Re: [SOLVED] Why is my swap space not used?

Is it in /etc/fstab?

No, it isn't. Can I just run genfstab again?

Last edited by catastropeia (2018-11-19 19:21:23)

Trilby

Inspector Parrot

Registered: 2011-11-29

Posts: 30,532

Website

Re: [SOLVED] Why is my swap space not used?

Can I just run genfstab again?

You can, yes.  But that seems a bit tedious.  All it does is write an fstab file which is just a plain text file: edit it as needed.

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"UNIX is simple and coherent" - Dennis Ritchie; "GNU's Not Unix" - Richard Stallman

catastropeia

Member

Registered: 2016-12-05

Posts: 10

Re: [SOLVED] Why is my swap space not used?

Thanks - that was it.