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I am packaging an application for ubuntu and the only reasonable repeatable test bed I've come up with is a machine running a live CD. I can't use a VM as the application requires 3d acceleration (VirtualBox's current solution doesn't cut it).

Unfortunately, the package is about 2GB, so it is unable to be installed, since the file system is around 4GB total. Just wondering if there's a way to increase the size of the file system in a way that would benefit what I'm trying to do?

Any further information about how Ubuntu live CD works out how large to create the FS?

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+1 Interesting question, – Tachyons Aug 15 '12 at 9:02
Must be forcefully a CD? You can do this with ease in a bigger size Live USB (let's say 8GB, 16GB, etc.) by creating a persistence file which will have additional +4GB to save your changes, installed software, etc. – Geppettvs D'Constanzo Aug 15 '12 at 12:09
It just about needs to be a CD because I need to make sure that every time I boot is 100% fresh original 'install', to make sure that my testing is perfectly repeatable. – Lynden Shields Aug 15 '12 at 22:27

The default LiveCD filesystem is stored entirely in RAM, so it's limited by how much physical RAM you have. I believe the default is to set it at ~50% of that number, striking a reasonable balance between temporary storage and enough memory to actually run stuff.

As the filesystem is necessarily very early on in the boot process, I believe it's setup by the kernel initramfs, so it would be difficult to change the ratio without building your own kernel.

Your best option is to switch to a LiveUSB and enable persistence, creating a multi-gigabyte on-disk file that will be used to store programs, downloads, etc. instead of RAM.

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Is there a way of making sure that the LiveUSB is restored to 100% original condition each boot (without having to completely rebuild the USB each time)? – Lynden Shields Aug 15 '12 at 22:29

You can remaster Ubuntu which is basically extracting files from the original CD, customize the system and compile again the image

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Any further information on how the customisation would be done to change the size of the file system? I couldn't see anything on the link regarding that specifically. – Lynden Shields Aug 15 '12 at 22:30

If you have a USB flash drive, you could install Ubuntu directly onto it from the live CD. Say you have a 8GB USB, the file system could use four, and Virtualbox can use the rest. If you have a larger USB, the better. Here is a link to the answer on how to install Ubuntu to a USB.

Hope this solves it.

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I need to resize the live CD's partition. I.e. once booted into the live cd, the / directory needs more free space. gparted only gives me access to repartition the hard drive which has the permanent partition on it; this isn't what I need. – Lynden Shields Aug 15 '12 at 7:28

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