#ipcs-s 你將會(huì )看到
key
0x00000000 68681743 apache 600
0x00000000 68714515 apache 600
0x00000000 68747291 apache 600
你可運行如下命令來(lái)安全的殺死每個(gè)Semaphore
#ipcrm -s<semid>
<semid>是上面ipcs-s輸出的第二列值。
想要一次性將所有的Semaphore全部殺死,請運行如下命令:
for semid in `ipcs-s |awk '{print $2}'`; do ip crm -s$semid; done
如果不能再創(chuàng )建更多的Semaphores:
有些時(shí)候你可能想改變系統允許創(chuàng )建semaphores的數量。這就需要改變內核參數。
如果你在虛擬機上運行而不能改變內核參數,請聯(lián)系你的主機提供商來(lái)改變這個(gè)參數。
運行以下命令來(lái)查看當前參數:
#ipcs-l
------ Shared Memory Limits --------
max number of segments = 4096
max seg size (kbytes) = 32768
max total shared memory (kbytes) = 8388608
min seg size (bytes) = 1
------ Semaphore Limits --------
max number of arrays = 1024
max semaphores per array = 250
max semaphores system wide = 256000
max ops per semop call = 32
semaphore max value = 32767
------ Messages: Limits --------
max queues system wide = 1024
max size of message (bytes) = 8192
default max size of queue (bytes) = 16384
修改 /etc/sysctl.conf文件,增加如下兩行:
kernel.msgmni = 1024
kernel.sem = 250 256000 32 1024
運行命令# sysctl-p
使剛改的參數生效。
(kernel.msgmni該文件指定消息隊列標識的最大數目,即系統范圍內最大多少個(gè)消息隊列。 缺省設置 :16)
另外延伸到/var/lock/subsys作用
關(guān)于/var/lock/subsys目錄總的來(lái)說(shuō),系統關(guān)閉的過(guò)程(發(fā)出關(guān)閉信號,調用服務(wù)自身的進(jìn)程)中會(huì )檢查/var/lock/subsys
下的文件,逐一關(guān)閉每個(gè)服務(wù),如果某一運行的服務(wù)在/var/lock/subsys下沒(méi)有相應的選項。在
系統關(guān)閉的時(shí)候,會(huì )像殺死普通進(jìn)程一樣殺死這個(gè)服務(wù)。
通過(guò)察看/etc/rc.d/init.d下的腳本,可以發(fā)現每個(gè)服務(wù)自己操縱時(shí)都會(huì )去查看
/var/lock/subsys下相應的服務(wù)。
例如:
[root@rrd init.d]# pwd
/etc/rc.d/init.d
[root@rrd init.d]# cat syslog
#!/bin/sh
#
# syslogStarts syslogd/klogd.
#
#
# chkconfig: 2345 30 99
# description: Syslog is the facility by which many daemons use to log
# messages to various system log files.It is a good idea to always
# run syslog.
# securlevel: 90
# processname: syslogd klogd
# Source function library.
. /etc/rc.d/init.d/functions
[ -f /sbin/syslogd ] || exit 0
[ -f /sbin/klogd ] || exit 0
if [ -f /etc/sysconfig/syslog ]
then
. /etc/sysconfig/syslog
else
SYSLOGD_OPTIONS="-m 0"
KLOGD_OPTIONS=""
fi
RETVAL=0
# See how we were called.
case "$1" in
start)
echo -n "Starting system logger: "
# we don't want the MARK ticks
daemon syslogd $SYSLOGD_OPTIONS
RETVAL=$?
echo
echo -n "Starting kernel logger: "
daemon klogd $KLOGD_OPTIONS
echo
[ $RETVAL -eq 0 ] && touch /var/lock/subsys/syslog
;;
stop)
echo -n "Shutting down kernel logger: "
killproc klogd
echo
echo -n "Shutting down system logger: "
killproc syslogd
RETVAL=$?
echo
[ $RETVAL -eq 0 ] && rm -f /var/lock/subsys/syslog
;;
status)
status syslogd
status klogd
RETVAL=$?
;;
restart|reload)
$0 stop
$0 start
RETVAL=$?
;;
*)
echo "Usage: syslog {start|stop|status|restart}"
exit 1
esac
exit $RETVAL
# cd /var/lock/subsys/
# ll syslog
-rw-r--r--1 root root 0 Jan 27 19:20 syslog
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