.ulg file maximum size?


We had the .ulg log file stop after 5.5 hours into a 8 hour flight. The log file size was 2 097 152 KB, there was no successive log for the remainder of the flight. Is there a maximum .ulg log file size? Running 1.12 based firmware with an 8 Gb SD card.
There is no mention of in ULog File Format | PX4 User Guide, and Logging | PX4 User Guide places emphasis on write speed.
Parameter Reference | PX4 User Guide SDLOG_PROFILE references “The default allows for general log analysis while keeping the log file size reasonably small.”
Is there a guide for what is reasonably small?


The 5.5h with 2GB file means 101KB/s logging rate. Is this with the default profile? I expect it to be around 40KB/s.
The maximum file size depends on the file system and OS, and the 2GB is apparently the size limit on NuttX, although it could go to 4GB.

Generally for this long flight hours we should further reduce the logging rate, as we don’t need high-rate sensor data.

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Thanks for the reply.

For the PX4 functions we are using SDLOG_PROFILE as 1 (the default set ), but we also have many more custom log messages which we are including so the logging rate is reasonable for us.

How would it be possible to split the log file into a further file after a file size of 2GB? In the short term what is the NuttX parameter to set the size limit to 4GB?

And to follow up we also got the logging rate down to 50KB/s, so up to max 11 hours flight time with a 2 GB limit.