Debian User Forums

So iam looking for a way to use the mkfs.btrfs command to setup a raid 10 before performing a raid10 installation. I was wondering if the mkfs.btrfs command is available using the net install iso?

This is coming from a Gentoo user who can install Linux mostly by CLI. I was wondering if there is any specific instructions on how to open a terminal and if there is a place where i can download the root file system and preform a custom install?

So far i booted to the ISO and started the install process and changed to a different TTY which gave me the option in busy box to run mkfs.btrfs. So i got that problem solved. Now the next question... where are the OS root files on the installation iso it self? and are they already uncompressed?

What do you mean by "OS root files" and why do you ask ?
Most installed files come from Debian packages (*.deb, which are compressed archives) from either installation media (under /cdrom/pool) or remote repositories.
If you do not want to follow the standard installation method, you'd better use the debootstrap method instead of trying to hack the installer.