Logging issues - time delays/jumps in logs

In copter-3.6 I am seeing drops in segments of log recordings.

The y-axis is diff(time) in seconds so most of the time logs are fine but I’m seeing on the order of 0.7-1 sec drops occasionally. Tested on two separate pixhawk 2.1’s - have not tried any different sd cards or settings.


Typically because the SD card isn’t playing nice - they tend to go out to
lunch reorganising themselves every now and then.

Mitigations include raising the log-file-bufsize or reducing the logging
rate by adjusting the log bitmask.

Corrections include using an SD card that doesn’t suffer from the problem
as much. Note that “more expensive” doesn’t necessarily mean better -
they can often be worse. 8GB/16GB silver-band sandisks seem to work well
for me.