fallocate -l 10485760 /tmp/tmp # create a 10MB file in /tmp

wget http://www.linuxquestions.org/ -B /tmp # saved a small index.html file in /tmp

# Size defaults for tmpfs filesystems mounted in early boot, before
# filesystems from /etc/fstab are mounted.
#
# NOTE: This file is deprecated.  Please see rcS(5) for details on how
# to configure tmpfs size limits.
#
# _SIZE variables are the maximum size (in bytes) that tmpfs
# filesystems can use.  The size will be rounded down to a multiple of
# the page size, 4096 bytes.  If no size is set, TMPFS_SIZE will be
# used as the default.
#
# Note that more complex mount options may be used by the creation of a
# suitable entry in /etc/fstab.  For example:
# 	tmpfs	/run	tmpfs	size=10%	0	0
# is equivalent to RUN_SIZE=10%, and will override the RUN_SIZE
# setting.  This will allow additional options such as nr_blocks and
# nr_inodes to be used, and also adjustment of the mode, nodev,
# nosuid, noexec options should any change from the defaults be
# necessary.

# TMPFS_SIZE: maximum size for all tmpfs filesystems if no specific
# size is provided.  If no value is provided here, the kernel default
# will be used.
TMPFS_SIZE=20%

# RUN_SIZE: maximum size of /run (was previously /var/run)
#
# Defaults to 10% core memory; the size required varies widely
# depending upon the demands of the software being run; this heuristic
# scales /run usage on system size.  Samba in particular has been seen
# to use at least 50MiB in a large heavily used server.  Typical usage
# is hundreds of KiB, maximum is tens of MiB.
RUN_SIZE=10%

# LOCK_SIZE: maximum size of /run/lock (was previously /var/lock)
#
# Typical usage: tens of KiB; maximum hundreds of KiB.  Default of
# 5MiB should ensure the limit is never reached.
LOCK_SIZE=5242880 # 5MiB

# SHM_SIZE: maximum size of /run/shm (was previously /dev/shm)
#
# No default size; the size required varies widely depending upon the
# demands of the software being run.
SHM_SIZE=

# TMP_SIZE: maximum size of /tmp
#
# No default size.
TMP_SIZE=

#
# /etc/default/rcS
#
# Default settings for the scripts in /etc/rcS.d/
#
# For information about these variables see the rcS(5) manual page.
#
# This file belongs to the "initscripts" package.

# delete files in /tmp during boot older than x days.
# '0' means always, -1 or 'infinite' disables the feature
TMPTIME=0

# spawn sulogin during boot, continue normal boot if not used in 30 seconds
SULOGIN=no

# do not allow users to log in until the boot has completed
DELAYLOGIN=no

# assume that the BIOS clock is set to UTC time (recommended)
UTC=yes

# be more verbose during the boot process
VERBOSE=no

# automatically repair filesystems with inconsistencies during boot
FSCKFIX=no

# mount /run/lock as a tmpfs (separately from /run)
RAMLOCK=yes

# mount /run/shm as a tmpfs (separately from /run)
RAMSHM=yes

# mount /tmp as a tmpfs
RAMTMP=no