During installation of Debian Linux, you are required to enter partition scheme. The easiest way is to use entire disk and recommended partition or you can decide yourself the partition. One of helpful detail of partition is given below:
swap = 2GB
file type for rest of partition = ext4
/ = 6GB
/opt = 10GB
/srv = 3GB
/tmp = 6GB
/usr = 10GB
/usr/local = 10GB
/var = 5GB
and finally for /home = rest of space left (but atleast 10GB).
This partition is on Logical Volume Manager – LVM. You can edit each partition later using GParted Live CD.
Note: This recommended partition is for end user’s laptop and desktop. For servers, /srv partition should be big enough for running services and /var partition must also be adjusted for maintaining log files.
For More info:
For partitioning multiple disks, guide can be found on tldp.