RANCID, the “Really Awesome New Cisco confIg Differ” (nice backronym, eh?) is a program that periodically goes out and fetches the config files from your routers / switches / many other devices that it supports. If you manage any of these type of devices, and do not currently use RANCID, well, all I can say is.. do it!
Why am I bringing this up now? We had a switch failure at work lately, and somehow while replacing the failed component, the switch managed to wipe it’s configuration (how? no idea.) Without RANCID, we would have been trying to figure out at least 4-5 months of configuration from the last time that the file was copied off the switch. We do have a RANCID server, which was unfortunately behind the switch that failed.. but fortunately, the server was being backed up by our BackupPC server, so we were able to hop on the web interface and grab a day-old config file. Even if we hadn’t had the BackupPC server, however, it would have only been a 15-minute job to recable the RANCID server onto a different switch and grab the config file from there — much better than the multi-hour job to rebuild the config of the failed switch. However, this does tell me that it’s actually not a bad idea to set up a job to regularly sync your switch config files from your RANCID server to an off-site machine.
In short: RANCID rocks! Use it!