My situation is that from time to time a specific process (in this case, it's Thunderbird) doesn't react to user input for a minute or so. I found out using
iotop that during this time, it writes quite a lot to the disk, and now I want to find out which file it writes to, but unfortunately
iotop gives only stats per process and not per open file(-descriptor).
I know that I can use
lsof to find out which files the process has currently open, but of course Thunderbird has a lot of them open, so this is not that helpful.
iostat only shows statistics per device.
The problem occurs only randomly and it might take quite some time for it to appear, so I hope I don't have to strace Thunderbird and wade through long logs to find out which file has the most writes.