soleilion I'm not too sure about storing logs/files on the switches, but we benefit greatly by aggregating logs, from all of our devices/servers/etc., into Kiwi. Once Kiwi receives those logs, they are stored in various flat files based on which device/type/purpose/locations/etc. they came from. Additionally, as has happened numerous times over the years, when a device goes down hard, and we cannot turn it up or log into it, while the first person is running troubles on the device, the second person is digging into the logs, alerts, etc. to find out what happened.
While I'm not sure how your environment is configured, I know having a solid, separate, standalone syslog server works very well for us. Going to a single server, then being able to view all of the logs from all of our devices, usually works out better for us.
Thank you,
-Will