When installing a Linux computer, this is a question I’ve been asked/asked myself many times, and it shall keep on being asked because things are not static and newer operating systems need more and more room as the basic software collection that you expect to get out of the box gets larger.
And the answer? Well – it depends 🙂 Specifically here I’m going to tackle the issue of desktop installs (i.e. the workstation for a single user), and specifically for Fedora – though it shouldn’t be much different for other operating systems in the same class – such as Ubuntu or SuSE.
The issue is basically only interesting if you want to put all the user’s files (i.e. the /home directory) in a different partition from the root file system, otherwise the question is moot – just lump everything into the root partition and be done with it.
It is highly recommended to have a separate home partition for user files as that makes upgrading to a new version of the operating system, recovery in case of a major system failure, or even jumping to a new Linux based operating system – so much easier.
It is so recommended that at least Fedora and SuSE create /home partitions in their default setup(1).
So the question that arises – how much room to leave to the operating system, as everything else goes into the user’s home partition.
My rule of thumb in the last few years, and its mostly still correct, is 16GB.
There’s really not much point putting in more then that, as even if you install tons of software, including huge things such as Open/Libre Office, the operating system and applications rarely take more then 10GB. Add a few things such as a small database for your pet project and some cache, and there’s really no need for more then 16GB (which is also a nice round number).
All this until you want to do a live operating system upgrade (preupgrade in Fedora-speak or dist-upgrade for you Ununtu/Debian users). When you want to do a full upgrade to the latest release of your operating system, while still running, your computer has to download and store all the software that has been updated in the new release – which is basically all of it – and this takes a lot of room. What prompted this post is that I wanted to do a live upgrade from Fedora 14 to Fedora 15 and needed 8.8GB of room on my root partition.
So – if you have upgrades in mind, don’t skimp on GBs for your root – any new harddrive packs at least 500GB, so make sure to reserve around 30 for your operating system. While it would most likely go to waste most of the time, when upgrade time comes – your life will be so much easier.