Just the answer:
By default, on Debian, the scroll back buffer is about 1K lines. This can be changed in the .screenrc file in your home directory. The following example sets the scroll back buffer to 5K lines.
Set the scroll back buffer on the fly with:
First enter the command line mode:
ctrl + a, :
To set the scroll back buffer to 2000 lines.
To actually scroll back, the actuall stuff why you may be reading this post:
First enter copy mode:
ctrl + a, [
Use standard VI controls to navigate through the lines (h j k l).
Use ctrl+b to scroll a full page up
Use ctrl+f to scroll a full page down.
For more details, please visit this link: