when setup the nextcloud, the error

{"reqId":"pGOMxGza9juKW0yMwiZb","level":3,"time":"2019-03-31T15:58:28+00:00","remoteAddr":"192.168.1.151","user":"georgewjj","app":"index","method":"GET","url":"\/settings\/ajax\/checksetup","message":{"Exception":"Error","Message":"Call to undefined function OC\\Settings\\Controller\\posix_getuid()"

it turned out requires a php module php-process to be installed, for PHP7.2

Then the admin checking processing will be work to check your environment and alert you the tuning suggestted

credit for :https://help.nextcloud.com/t/health-check-failing-and-repeating-posix-g…