Dont make one big root filesystem

From FBSD_tips

Simple is good, except when it isn't.

It might be tempting to make one big root filesystem. There are reasons that this might seem like a good idea. Like not having to guess at how big to make things like /tmp and /var. Do not be enticed by this illusion of simplification of administration.

Bad things that can happen with "one giant root" :

• You can not enable softupdates on root, so no bg_fsck.
• If the one big partition goes flooky, you can not get a shell until the whole filesystem fixes (long time).
• Dealing with a filled /var is much easier than dealing with a filled root.
• Quotas are enabled on a filesystem basis
• noexec and other options are enabled on a filesystem basis (e.g. for /tmp)
• Snapshots (which have many uses) are done on a filesystem basis.