Help interpreting my /etc/fstab file?

Jont828 · 2019-10-31 02:25:46

I'm trying to investigate issues with my swap partition, namely that the system doesn't seem to be using any more than around 400 MB of swap space, even when memory is full. Before, it used to use 3-4 GB fairly liberally when RAM was running out, and even changing the swappiness didn't help. Anyhow, here's my fstab file: I can't seem to find anything about a swap partition in it, so I'm suspecting that might be the issue.

# Static information about the filesystems.
# See fstab(5) for details.

# <file system> <dir> <type> <options> <dump> <pass>
# /dev/nvme0n1p7
UUID=ba8e5456-cac1-4e0d-848e-80a0ebe631ba	/         	ext4      	rw,relatime,data=ordered	0 1

/dev/disk/by-uuid/8282531d-2883-43fc-8df9-98e14d0e1d1e /mnt/8282531d-2883-43fc-8df9-98e14d0e1d1e auto nosuid,nodev,nofail,x-gvfs-show 0 0
/dev/disk/by-uuid/4AB0EB3DB0EB2E5F /mnt/4AB0EB3DB0EB2E5F auto nosuid,nodev,nofail,x-gvfs-show 0 0

Where the UUIDs correspond to

NAME        FSTYPE LABEL     UUID                                 FSAVAIL FSUSE% MOUNTPOINT
nvme0n1                                                                          
├─nvme0n1p1 vfat   SYSTEM    26E8-0862                                           
├─nvme0n1p2                                                                      
├─nvme0n1p3 ntfs   Windows   4AB0EB3DB0EB2E5F                       68.2G    43% /mnt/4AB0EB3DB0EB2E5F
├─nvme0n1p4 ntfs   WinRE_DRV 01D3FED326CCD8F0                                    
├─nvme0n1p5 ext4             8282531d-2883-43fc-8df9-98e14d0e1d1e   75.2G    17% /mnt/8282531d-2883-43fc-8df9-98e14d0e1d1e
├─nvme0n1p6 ext4             ba8e5456-cac1-4e0d-848e-80a0ebe631ba   42.9G    77% /
└─nvme0n1p7 swap             48105f47-3f73-4450-b774-a504d280a445                [SWAP]

Am I good just adding the line

UUID=48105f47-3f73-4450-b774-a504d280a445 none swap defaults 0 0

to it? As a follow up, what does <pass> mean instead of <fsck>? I'm just looking for a second opinion before I modify anything important to avoid the risk of bricking my laptop.

Last edited by Jont828 (2019-10-31 02:26:23)

efexos · 2019-10-31 02:37:10

yup you are good "UUID=xxxxxxxxxxxxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxxxxxxx none swap defaults,pri=-2 0 0" you may need to generate new grub.cfg do that as well.

fukawi2 · 2019-10-31 02:41:48

What is the output of `swapon`?

Jont828 · 2019-10-31 02:43:21

The output of `swapon` is

NAME           TYPE       SIZE   USED PRIO
/dev/nvme0n1p7 partition 15.6G 522.3M   -2

As a follow up question, what exactly does a priority of -2 mean? I thought priorities were typically either 0, 1, or 2.

sabroad · 2019-10-31 03:26:55

Jont828 wrote:

my fstab file: I can't seem to find anything about a swap partition in it, so I'm suspecting that might be the issue.

If any swap is being used, then something has activated it, if not fstab. Duplicating it here won't have effect.

Jont828 wrote:

the system doesn't seem to be using any more than around 400 MB of swap space, even when memory is full.

How do you know the memory is full? Linux ate my RAM

loqs · 2019-10-31 08:32:52

Jont828 wrote:

As a follow up question, what exactly does a priority of -2 mean? I thought priorities were typically either 0, 1, or 2.

https://github.com/torvalds/linux/commi … 819ff5f94a
Edit:

Jont828 wrote:

As a follow up, what does <pass> mean instead of <fsck>? I'm just looking for a second opinion before I modify anything important to avoid the risk of bricking my laptop.

See `man 5 fstab`.

Last edited by loqs (2019-10-31 09:18:06)

Arch Linux

#1 2019-10-31 02:25:46

Help interpreting my /etc/fstab file?

#2 2019-10-31 02:37:10

Re: Help interpreting my /etc/fstab file?

#3 2019-10-31 02:41:48

Re: Help interpreting my /etc/fstab file?

#4 2019-10-31 02:43:21

Re: Help interpreting my /etc/fstab file?

#5 2019-10-31 03:26:55

Re: Help interpreting my /etc/fstab file?

#6 2019-10-31 08:32:52

Re: Help interpreting my /etc/fstab file?

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