Flashybrid

http://hacks.slashdirt.org/sw/flashybrid/

apt-get update
apt-get install rsync
wget http://hacks.slashdirt.org/sw/flashybrid/flashybrid_0.21_all.deb
dpkg -i flashybrid_0.21_all.deb

/etc/default/flashybrid:

# This file controls the flashybrid init script.

# Whether to start flashybrid on boot, and shut it down on shutdown.
# This has the potential to break your system if it is turned on, so
# make sure you understand flashybrid, and have configured it for your
# system, before turning this on.
ENABLED=yes

# Whether to display a message before a directory is synchronized or not.
VERBOSE=yes

/etc/flashybrid/config:

# This is the main configuration file for the flashybrid system.

# The space-separated mountpoint(s) of your flash memory.
# Support for multiple mountpoints is experimental. Because mountpoints
# are space-separated, they must not have a space in their full path.
# example: FLASHMOUNT="/ /srv"
FLASHMOUNT="/"

# You probably want a ramdisk to be set up with directories that the system
# needs to write data to frequently, so that your flash disk can be mounted
# read-only. Flash memory can only be written to several thousand times over
# its lifetime, so setting up a ramdisk will extend the lifetime of your
# flash a lot. This is the location to mount the ramdisk. Comment out the
# line to not set up a ram disk.
RAMMOUNT=/ram

# This controls the maximum ammount of memory you want to allocate  
# to the tmpfs RAM drive
# This parameter is optional, and if you do not supply if, tmpfs will
# occupy up to 50% of your available memory (ram+swap)
# FLASH_MAX=92m

# You may also want to edit the other files in this directory:
# ramtmp, ramstore

/etc/flashybrid/ramstore:

# This is a list of directories that are used to store variable data
# that is written to during normal operation of the system, and that should
# be preserved across reboots.
#
# On boot, the listed directories on your flash disk will be copied to the
# ram disk, and then bind mounts will be used to make the directories on
# the ram disk replace them.
#
# On shutdown, the contents of those directories on the ramdisk will be
# rsynced back to the flash disk.
#
# Directories listed here that are not present will be silently ignored. 
# Do not put the trailing slash on directories!

# Should always be in ram disk.
/etc
/var/lib/alsa
/var/lib/asterisk
/var/lib/discover
/var/lib/dbus
/var/lib/exim4
/var/lib/op-panel
/var/lib/logrotate
/var/lib/mysql
/var/log
/root

# If you don't use devfs/udev, you will want /dev in ram, since many things
# need to modify it when the system is running. Not needed on systems
# running udev.
#/dev

# Necessary if the system is to be able to send mail while in embedded
# mode.
/var/spool
/var/mail

# Some daemons might require write access to subfolders of /var/cache,
# it might be a good idea to add these subfolders here or make the whole
# of /var/cache mirrored in tmpfs. Note that this is likely to be wasteful
# (large amount of data to be held in tmpfs)
#/var/cache