Strange insufficient storage space exception

[CharlieZhao2023]

I got an exception when allocating a new publisher:

(-12) insufficient storage space [aeron_driver_context_run_storage_checks, aeron_driver_context.c:1198] insufficient usable storage for new log of length=50335744 usable=0 in /dev/shm/aeron

However, at the time when I got the exception, the output was as follows:

$ df -h /dev/shm
Filesystem Size Used Avail Use% Mounted on
tmpfs 1.9G 442M 1.5G 24% /dev/shm

$ free -h
total used free shared buff/cache available
Mem: 3.7Gi 425Mi 167Mi 450Mi 3.1Gi 2.6Gi
Swap: 0B 0B 0B

There should be enough shared memory (shm) to allocate the new publisher channel. Why did it throw this exception?

I have started the same process 4 times, and the previous allocations were okay. The 5th attempt triggered the exception.