无法通过ini标志启动uwsgi进程

uwsgi --ini file.ini

没有任何uwsgi pids

ps aux | grep uwsgi
root     31605  0.0  0.3   5732   768 pts/0    S+   06:46   0:00 grep uwsgi

file.ini

[uwsgi]

chdir =/var/www/lvpp/site

wsgi-file =/var/www/lvpp/lvpp.wsgi

master = true

processes = 1

chmod-socket=664

socket = /var/www/lvpp/lvpp.sock

pidfile= /var/www/lvpp/lvpp.pid

daemonize =/var/www/lvpp/logs/lvpp.log

vacuum = true

uid = www

gid = www

env = DJANGO_SETTINGS_MODULE=settings

文件lvpp.log

*** Starting uWSGI 2.0.10 (32bit) on [Wed Apr  8 06:46:15 2015] ***
compiled with version: 4.4.7 20120313 (Red Hat 4.4.7-11) on 17 March   2015 21:29:09
os: Linux-2.6.32-431.29.2.el6.i686 #1 SMP Tue Sep 9 20:14:52 UTC 2014
machine: i686
clock source: unix
pcre jit disabled
detected number of cpu cores: 1
current working directory: /var/www/lvpp
writing pidfile to /var/www/lvpp/lvpp.pid
detected binary path: /var/www/lvpp/site/env/bin/uwsgi
setgid() to 503
setuid() to 501
chdir() to /var/www/lvpp/site/
your processes number limit is 1812
your memory page size is 4096 bytes
detected max file descriptor number: 1024
lock engine: pthread robust mutexes
thunder lock: disabled (you can enable it with --thunder-lock)
error removing unix socket,unlink(): Permission denied [core/socket.c  line 198]
bind(): Address already in use [core/socket.c line 230]

它起得很早.
但是当我调用kill -9 uwsgi.pid时,我无法再次启动uwsgi进程.

请告诉我,为什么我可以再次启动uwsgi进程？
谢谢