Make ubuntu persistent live iso faster - bash

Question

First, I want to share my experience about how to make a USB pendrive of Ubuntu live iso, which is multiboot and it can duplicate itself by a bash code. I am trying to guide you to make something like that, then, as long as I'm not an expert, asking how can I make it faster(while booting, operating or cloning)?
First of all, you should partition your usb flash driver to two partitions by some tools like GParted. One fat32 partition and the other ext2 with the fix size of 5500MB(if you change its size then you have to change this number in the bash code too). You can find the size of the first partition by the whole size of your usb flash drive minus the size of second partition.
Second, you must download ubuntu iso image(I downloaded lubuntu 13.10 because it's faster, but I think ubuntu must work too) then copy it in the first partition(the fat32 partition.) and rename it to ubuntu.iso.
Third, run this command to install grub bootloader(you can find this command in the bash code too)
sudo grub-install --force --no-floppy --boot-directory=/mnt/usb2/boot /dev/sdc1
"/mnt/usb2" directory is the one that you mounted the first partition and /dev/sdc1 is its device. If you don't know about this information just use fdisk -l or Menu->Preferences->Disks to find out. Then copy the following files in their mentioned directories and reboot to usb flash(for my motherboard by pushing F12 then selecting my flash device from the "HDD Hard" list .)
/path to the first partition/boot/grub/grub.cfg
set timeout=10
set default=0
menuentry "Run Ubuntu Live ISO Persistent" {
loopback loop /ubuntu.iso
linux (loop)/casper/vmlinuz persistent boot=casper iso-scan/filename=/ubuntu.iso noeject noprompt splash --
initrd (loop)/casper/initrd.lz
}
menuentry "Run Ubuntu Live ISO(for clone to a new USB drive)" {
loopback loop /ubuntu.iso
linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=/ubuntu.iso noeject noprompt splash --
initrd (loop)/casper/initrd.lz
}
the bash code:
/path to the first partition/boot/liveusb-installer
#!/bin/bash
destUSB=$1
# insert mountpoint, receive device name
get_block_from_mount() {
dir=$(readlink -f $1)
MOUNTNAME=`echo $dir | sed 's/\\/$//'`
if [ "$MOUNTNAME" = "" ] ; then
echo ""
return 1
fi
BLOCK_DEVICE=`mount | grep "$MOUNTNAME " | cut -f 1 -d " "`
if [ "$BLOCK_DEVICE" = "" ] ; then
echo ""
return 2
fi
echo $BLOCK_DEVICE
return 0
}
sdrive=$(echo $destUSB | sed 's/\/dev\///')
if ! [ -f /sys/block/$sdrive/capability ] || ! [ $(($(< /sys/block/$sdrive/capability )&1)) -ne 0 ]
then
echo "Error: The argument must be the destination usb in /dev directory!"
echo "If you don't know this information just try 'sudo fdisk -l' or use Menu->Prefrences->Disks"
exit 1
fi
srcDirectory=/isodevice
srcDev=`get_block_from_mount $srcDirectory`
srcUSB="${srcDev%?}"
if [ $srcUSB == $destUSB ]; then
echo "Error: The argument of device is wrong! It's the source USB drive."
exit 1
fi
diskinfo=`sudo parted -s $destUSB print`
echo "$diskinfo"
# Find size of disk
v_disk=$(echo "$diskinfo"|awk '/^Disk/ {print $3}'|sed 's/[Mm][Bb]//')
second_disk=5500
if [ "$v_disk" -lt "6500" ]; then
echo "Error: the disk is too small!!"
exit 1
elif [ "$v_disk" -gt "65000" ]; then
echo "Error: the disk is too big!!"
exit 1
fi
echo "Partitioning ."
# Remove each partition
for v_partition in $(echo "$diskinfo" |awk '/^ / {print $1}')
do
umount -l ${destUSB}${v_partition}
parted -s $destUSB rm ${v_partition}
done
# Create partitions
let first_disk=$v_disk-$second_disk
parted -s $destUSB mkpart primary fat32 1 ${first_disk}
parted -s $destUSB mkpart primary ext2 ${first_disk} ${v_disk}
echo "Formatting .."
# Format the partition
mkfs.vfat ${destUSB}1
mkfs.ext2 ${destUSB}2 -L home-rw
echo "Install grub into ${destUSB}1 ..."
mkdir /mnt/usb2
mount ${destUSB}1 /mnt/usb2
grub-install --force --no-floppy --boot-directory=/mnt/usb2/boot $destUSB
cp $srcDirectory/boot/grub/grub.cfg /mnt/usb2/boot/grub
cp $srcDirectory/boot/liveusb-installer /mnt/usb2/boot
echo "Copy ubuntu.iso from ${srcUSB}1 to ${destUSB}1......"
cp $srcDirectory/ubuntu.iso /mnt/usb2
umount -l ${destUSB}1
rm -r /mnt/usb2
echo "Copy everything from ${srcUSB}2 to ${destUSB}2 ............"
dd if=${srcUSB}2 of=${destUSB}2
echo "It's done!"
exit 0
So after that if you want to clone this flash, just reboot to the second option of grub boot loader then put another usb flash drive on and run liveusb-installer /dev/sdc. It will make another usb drive with every installed apps from the first one into /dev/sdc drive. I made this code so all of my students have the same flash drive to practice programming with c, python or sage everywhere. The speed of non-persistent (the second option in grub menu) is fine, but the fist option, which is the persistent one, is take 3-4 min to boot and after that its a little bit slow! Also, the installation(duplication) take a half an hour to complete! Is there any improvement to make it faster in any way?
any suggestion will be appreciated

Answer 1

As I said before, if lubuntu boots non-persistent, it will be faster. So I infer that if I just keep home directory persistent then the rest of folders of root directory would be in the RAM, then it must be faster. For achieving this, I changed it a little bit to boot with /home persistent and install every application after each boot, automatically. It's turned out in this way the boot time doesn't changed(booting + installing) but operating is so faster, which is great for me.
I didn't change grub.cfg at all. I changed the bash code(liveusb-installer) to label the second partition to home-rw, so the rest of folders just stay in RAM.
In the bash code: /path to the first partition/boot/liveusb-installer, just change the line of mkfs.ext2 ${destUSB}2 -L casper-rw to mkfs.ext2 ${destUSB}2 -L home-rw.
After changing liveusb-installer you can use that when you want to clone this USB drive. If you installed it before(by using above recipes) then just go to second option of grub menu(the non-persistent one) then format the second partition and label it to home-rw. After that just reboot to first option of grub menu, then become online and install any program that you wish to be there always.
sudo apt-get update
sudo apt-get install blablabla
After installing, copy every packages and lists to ~/apt directory by running these commands:
mkdir ~/apt
mkdir ~/apt/lubuntu-archives
mkdir ~/apt/lubuntu-lists
cp /var/cache/apt/archives/*.deb ~/apt/lubuntu-archives
cp /var/lib/apt/lists/*ubuntu* ~/apt/lubuntu-lists
Now copy following files in ~/apt directory
/home/lubuntu/apt/start-up
#!/bin/bash
apt_dir=/home/lubuntu/apt
# This script meant to open by /home/lubuntu/apt/autostart
for file in $(ls $apt_dir/lubuntu-archives)
do
ln -s $apt_dir/lubuntu-archives/$file /var/cache/apt/archives/$file
done
for file in $(ls $apt_dir/lubuntu-lists)
do
ln -s $apt_dir/lubuntu-lists/$file /var/lib/apt/lists/$file
done
apt-get install -y binutils gcc g++ make m4 perl tar \
vim codeblocks default-jre synapse
exit 0
Also change the above packages to blablabla of the install command.
/home/lubuntu/apt/autostart
#!/bin/bash
# This script meant to open by /home/lubuntu/.config/lxsession/Lubuntu/autostart
# or autostart of "Menu->Perferences->Default applications for LXSession"
xterm -e /usr/bin/sudo /bin/bash /home/lubuntu/apt/start-up
synapse
Then edit this file /home/lubuntu/.config/lxsession/Lubuntu/autostart and add the address of above file into it. Like this:
/home/lubuntu/apt/autostart
Now after each reboot a nice terminal will be opened and all the packages will install as I wish! The advantage of this method over persistent root directory is the much faster operation, for instance, opening windows or running programs. But the time of cloning and booting are steal long. I will be so glad that anybody helps me to make it more professional and faster.