The trace log is a log of diagnostic events that SonicWall records into an area of its memory that is persistent through reboot. After a reboot that recorded during the previous session is saved to non-volatile flash during startup, where the last 8 trace logs are saved.
This article explains how to download each of the four trace log options available through the Diag page of the SonicWall firewall.
Current are the logs from the current session (i.e. since the last reboot). Although they won’t have anything leading up to a crash, they are generally worth including because even warnings from after a crash can sometimes help to see what is going on.
Last has the logs from the session before the last reboot and can be useful after a crash to see what went on leading up to the crash. It is included in the All trace logs so generally if you pull “All” then you don’t need to also pull “Last”. But in the specific case where you know that you are pulling them shortly after a crash it can be nice to have this separate from All.
All contains all saved trace logs from previous sessions, but does not include the current ones. It does include the “Last” trace logs.
All + Current option includes “All” as above, plus the current logs that are not included in “All”. If you pull this then you get everything in a single download and so do not need to download anything else. That is its purpose, to make it easy and avoid needing to pull multiple log files.
Here's how to download trace logs:
Log on to the Firewall via http or https. For instance: https://172.27.60.78/main.html. If your SonicWall web management is listening on a custom port then please add the custom port number after the IP address in URL.