I'd like to change the default size of /dev/shm in Lubuntu 11.10 (also known as /run/shm now, I guess).

It doesn't seem to appear in my fstab:

# / was on /dev/sdb5 during installation
UUID=66ac63f0-45fa-4766-9d20-7c56bcd0460d /               ext3    noatime,errors=remount-ro 0       1
# /home was on /dev/sdb7 during installation
UUID=227f1b29-5d04-4c28-9c9c-ea70b1726434 /home           ext3    noatime         0       2
# swap was on /dev/sdb6 during installation
#UUID=9e13b7cc-1f75-4b4e-9e79-c0f7368de353 none            swap    sw              0       0
/dev/mapper/cryptswap1 none swap sw 0 0

tmpfs /tmp tmpfs defaults,noexec,nosuid 0 0
tmpfs /var/tmp tmpfs defaults,noexec,nosuid 0 0

Try putting a /dev/shm line in the fstab file to override the default settings:

tmpfs /dev/shm tmpfs defaults,noexec,nosuid,size=100M 0 0

If that doesn't work, you can try remounting it after it's been mounted at boot, for example by putting this line into the /etc/rc.local file

mount -o remount,size=100M /run/shm
  • 1
    The remounting works. The fstab suggestion does not. We need something better...
    – Richard
    Feb 27 '12 at 18:45
  • Leastwise, this doesn't work in 11.10: see comments here.
    – Richard
    Feb 27 '12 at 18:59
  • 1
    Shouldn't it be /dev/shm? Nov 27 '17 at 21:58
  • Mine is filling up with pulse-shm-##### files and I need to know why I should allow it to do it at all. Certainly I don't want my SSD filling up with temp files at all. The whole system is on a 160 SSD.
    – SDsolar
    Mar 5 '18 at 20:32

Temporary increase tmpfs filesystem

1) Open /etc/fstab with vi or any text editor of your choice,

2) Locate the line of /dev/shm and use the tmpfs size option to specify your expected size, - e.g. 512MB:

tmpfs      /dev/shm      tmpfs   defaults,size=512m   0   0

e.g. 2GB:

tmpfs      /dev/shm      tmpfs   defaults,size=2g   0   0
mount -o remount /dev/shm
  • 1
    It doesn't seem to appear in my fstab
    – Michael
    Apr 20 '19 at 1:42

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