There is an AIX subforum here - post AIX problems there next time please^^
How did you notice it is locked up? Can you please post a vmstat -vs? An iostat of the disk(s) on which the problematic filesystems is placed on could help too.
Edit: Are you using AIO? If yes, "lsattr -El aio0" and "ps aux| grep aioserver" and iostat with -AQ to check aio queues maybe, please, ty
What kind of application is causing that traffic?