[arch-general] Almost system crash, users getting logged out

[Ralf Mardorf]

On Sat, 5 Nov 2016 12:09:35 +0100 (CET), J. C. wrote:
>1.7G [snip] That does seem a lot.

Hi Jeanette,

no, it isn't, you're most likely fooled by the confusing output of df.

Assuming you're still using fstab, then as long as there isn't an
explicit uncommented entry in fstab, tmpfs takes around half of the
available memory. In your case just one time 1,7G for tmpfs as a whole.

I suspect you have 4 GiB of RAM and a 

[rocketmouse at archlinux ~]$ df -h|head -1;df -h|grep tmpfs
Filesystem      Size  Used Avail Use% Mounted on
tmpfs           1.9G  4.0K  1.9G   1% /dev/shm
tmpfs           1.9G     0  1.9G   0% /sys/fs/cgroup
tmpfs           1.9G  8.0K  1.9G   1% /tmp
tmpfs           371M   32K  371M   1% /run/user/1000
[rocketmouse at archlinux ~]$ grep tmpfs /etc/fstab
#tmpfs          /tmp        tmpfs nodev,nosuid,size=3G     0 0
[rocketmouse at archlinux ~]$ hwinfo --memory | grep Size
  Memory Size: 3 GB + 512 MB
[rocketmouse at archlinux ~]$ uname -m
x86_64

An issue I experience since a very long time is, that I'm missing
256 MiB, since the frame buffer size should be 256 MiB, due to BIOS
settings, so I expect 3 GiB + 768 MiB. I guess the missing 256 MiB
aren't reserved for the kernel, since the output of hwinfo years ago
didn't made such arbitrary calculations.

>None of that is part of my /etc/fstab, so the next question would be:

Btw. it's possible to directly use systemd to mount, without keeping an
fstab.

Regards,
Ralf