Graceful restart

[Mark]

We just started using Cassandra 0.6.4 yesterday for simple logging of a 
particular action. This is pretty much experimental for us at this stage 
so we only have 1 node up and running (no gasps please). My question is 
how can I add another column family (ie alter storage-conf.xml) without 
disrupting service. Is there some sort of graceful restart?

Going forward, how is this accomplished with a multi-node architecture? 
Thanks