upload_tmp_dir is not set in my php.ini either. sys_get_temp_dir() returns /tmp
should i set it anyway?
/tmp has 4.2gig free. according to graphs it got as low as 3.9gig yesterday.
restarting lsws means that the problem goes away for some time. seems to come back on its own for no reason.
for example, I just uploaded a 10mb file with no problem. while it was uploading I could see /tmp/phpnMUhZ6 getting filled.