I have a USB drive (a Drobo) that appears disconnecting randomly after 10-20 hours. I'm trying to gather data to help understand the root cause of the problem so I'd like to understand the timing of the disconnection. Is there a log file that would have this kind of data ? On a related note, is there a log that would have generally relevant data that I could use to try to correlate to the disconnections?
Yes, there are log files with a ton of information. If you go to the Applications folder there is a folder named utilities inside of it. Inside the utilities folder, is an app called console.app. This will show you all the system generated messages. You can search for different keywords or look for different times.
I can only guess at keywords to search on. I'd start with word "Error" or maybe "disconnected". If you know your device name or number you can search on that. There is also a folder in the console app called "System Reports" that should have what you want.