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Re: is it possible to install a custom initramfs USB bootable system?


As I pointed out on debian-user, where this question was asked as well,

On Sat, Feb 21, 2009 at 02:58:21PM +0100, Miernik wrote:
> Hello,
> I have a computer with 10 GB of RAM, but no hard disks. I want to
> install Debian to make it work this way:
>  1. Debian is installed in RAM (maybe from PXE netboot)

If you have an environment capable of PXE booting, there's a good chance
you can set up an NFS root. 

>  2. with some command a compressed squashfs image is created of the
>     current system, and saved on an USB flash stick
>  3. the next time the system needs to be booted, it is booted from this
>     USB flash stick, fetched and uncompressed totally into RAM, and then
>     this flash stick is removed (it should not be needed for this stick
>     to stay inserted while the system works, only for boot)
>  4. when (after) the system is upgraded (in live initramfs), a command
>     (from point 2.) is run again to update the compressed squashfs image
>     on the USB stick

This means that every change requires recreating a squashfs filesystem.
Which means a longer cycle for fixing problems. It also implies that a
reboot is required to properly test things without your local changes.

In addition to that, a squashfs is inherently slower than a standard
file system.

How much do you need to optimize the boot time? 'toram' means reading a
large file (over the network in your case) at startup and hence a rather
slow boot.

               Tzafrir Cohen
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http://www.xorcom.com  iax:guest@local.xorcom.com/tzafrir

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