Thanks for the recommendation! Unfortunately, that didn't seem to make much of a difference. Might be that I'm only writing to the file from a single node (there are 8x threads in the application). In fact, the config that yields the highest throughput is using only the "localflocks" option (with nothing else). Wierd...

ocfs2 file system test
From fio, 8x jobs to a single file
jobocfs2-R0-1: (groupid=0, jobs=8): err= 0: pid=7716: Thu Jan 16 06:01:40 2020
write: IOPS=8278, BW=8279MiB/s (8681MB/s)(485GiB/60002msec)
slat (usec): min=142, max=812399, avg=962.75, stdev=13224.77
clat (usec): min=46, max=813134, avg=2897.54, stdev=22854.13
lat (usec): min=386, max=813504, avg=3860.69, stdev=26365.31

ext4 file system test for baseline of hardware, shows that the hardware can do more than 8GB/sec
From fio, 8x jobs to a single file
write: IOPS=18.3k, BW=17.9GiB/s (19.2GB/s)(1075GiB/60002msec)
slat (usec): min=154, max=2428, avg=215.03, stdev=25.61
clat (usec): min=275, max=6916, avg=1528.54, stdev=91.62
lat (usec): min=542, max=7103, avg=1743.82, stdev=91.47

Anyone hit a higher limit on OCFS2 than 8GB/sec?

Or... Are there any internal utilities/logs that I can use to see what OCFS2 is doing when it gets to 8GB/sec?