What tools are available for persistent storage in ROS?

edit

I decided there was apparently no generalized/robust way to persist information using the ROS infrastructure, so I wrote something myself: https://github.com/MisoRobotics/persi... That package allows the user to read from and write to ROS topics and this node will take care of ensuring that the topic is populated with the message from last session next time the system is started up.

EDIT: This actually doesn't work (well) because of the way ROS topics are architected. If a topic represented a series of messages that supersede each other (the way I assumed it would work since that seems like the vast majority of use cases, and is the way it works within a single node), this would work great. Instead, a topic just represents a set of instantaneous messages with no assumption of precedence or behavior -- sometimes, as in the case of /tf_static, messages on a topic represent the accumulation of information instead of a sequence of information. If there are two nodes who each have a latched message where the type doesn't include a timestamped header, how a subscriber should interpret the message pair they'll receive upon subscription is completely undefined.