Partman automatic partition within preseed file

Question

Can anyone explain to me what the numbers 512 512 512 mean?

string dom0-domU :: 

512 512 512 ext3

$primary{ }

$bootable{ }

method{ format } format{ }

use_filesystem{ } filesystem{ ext3 }

mountpoint { /boot }

How would I make a 137GB and a 20GB partition?

Also, if the PC has more than one hard drive, how do you ensure only the one you want to install linux on gets edited?

Answer 1

The three numbers are the minimum size of the disk, the priority, and the maximum size. The priority is used when partman is trying to fit several partitions onto the disk: the higher it is, the more likely that partition is to get the maximum size it asks for.

If there is more than one disk, it's something like:

d-i partman-auto/disk multiselect /dev/sda