sorry, i know this thread's a little dusty now, but i just cant let this go without passing comment...
It's not only possible, breakage from an update is probably inevitable with Arch or any other rolling release. By definition, you are dealing with bleeding edge software that has not been thoroughly tested and which is in a constant state of flux with a rolling release. Bugs are inevitable and sooner or later one of those bugs will break your system.
not all rolling releases are alike. rolling release, does not, by definition, mean bleeding edge, despite what impression using arch may give you of rolling release.
for example, gentoo, when staying with the stable keyword (i.e. the keyword with just your architecture with no "~" prefix, and certainly no "**" keyworded packages)
, the "probably inevitable" of something breaking, is as diminished as any other stable non-rolling release (maybe more so?). it's stable ("old", farther from the edge), and it's still rolling release. (not to mention the rest of the checks, balances, safeguards, and tools to empower etc that gentoo has to remedy any such update issues, like slots, or painless rolling back of problem packages... not that you see much of that sort of thing when sticking with just stable).[/edit]
sry, i just didnt want to leave that hanging there giving people a bit of a misconception of what rolling release is, or can be.
but yeah... in the context of arch... there is no stable. you're always right up there on the bloodied edge.
.... unless you want to go for archserver, which i think was created to address that problem, so an arch[-like] system could be used in a server environment where such volatility is not welcome. ... but i think it's repo is lacking anything not specifically server-related.
~ i've never used archserver for long enough, so cannot profess to know if it actually does achieve the goal of being able to update arch without relatively high risk of breakages.