The default for installing is to shrink any existing partitions for whatever OS is already on the machine. You could simply overwrite any previous OS, but then SUSE pushes on you a partition scheme that I find hard to use. I like to build stuff from source, and the root partition is simply too small. Instead, I favor having the entire system in one root partition.
During the installation process, you’ll come to a step for partitioning the hard drive. If you intend to keep your old OS, SUSE can do a fine job of shrinking the original and making room to dual boot. However, I highly recommend you de-select for “Propose Separate Home Partition.”
If you want to wipe the drive and give it all to SUSE, it’s a little tricky because it’s not obvious. From this page, after de-selecting the separate home partition option, click “Create Partition Setup.”
On the next page, click the radio button for your disk description (usually the fist option). Click “Next.”
On the next page, select “Use Entire Disk” making sure the separate home option is still de-selected. Make sure all the current partitions are selected for removal. Click “Next.”
A new suggested change should give you a small SWAP partition (you shouldn’t argue with that) and a large main partition for everything else. Walk through the rest as you normally would.
