sysctl 的问题

tenya

我很奇怪，本来，我一开始执行sysctl -a看到很多信息的。后来记得我执行后 sysctl -w kernel.core_pattern=core.%p.%t 后，再用sysctl -a 查询一下，发现什么也看不到，变空了。请问哪位大哥知道这是怎么回事。
重启后也不行。

tomshenhao

sysctl -p: Load in sysctl settings from the file specified or /etc/sysctl.conf if none given.
or check the file /etc/sysctl.conf

tenya

回复 2# tomshenhao

你看一下：

$ sysctl -p
[root] /root
$
$ cat /etc/sysctl.conf
# Kernel sysctl configuration file for Red Hat Linux
#
# For binary values, 0 is disabled, 1 is enabled.  See sysctl( and
# sysctl.conf(5) for more details.

# Controls IP packet forwarding
net.ipv4.ip_forward = 0

# Controls source route verification
net.ipv4.conf.default.rp_filter = 1

# Do not accept source routing
net.ipv4.conf.default.accept_source_route = 0

# Controls the System Request debugging functionality of the kernel
kernel.sysrq = 0

# Controls whether core dumps will append the PID to the core filename.
# Useful for debugging multi-threaded applications.
kernel.core_uses_pid = 1

# Controls the use of TCP syncookies
net.ipv4.tcp_syncookies = 1

# Disable netfilter on bridges.
#net.bridge.bridge-nf-call-ip6tables = 0
#net.bridge.bridge-nf-call-iptables = 0
#net.bridge.bridge-nf-call-arptables = 0

# Controls the default maxmimum size of a mesage queue
kernel.msgmnb = 65536

# Controls the maximum size of a message, in bytes
kernel.msgmax = 65536

# Controls the maximum shared segment size, in bytes
kernel.shmmax = 68719476736

# Controls the maximum number of shared memory segments, in pages
kernel.shmall = 4294967296

kernel.sem=550 320000 350 4096

#-----------------------------------------
net.ipv4.tcp_keepalive_intvl = 75
net.ipv4.tcp_keepalive_probes = 9
net.ipv4.tcp_keepalive_time = 300




   

tenya

自己顶一下，不然就沉了。

tomshenhao

那你现在执行sysctl -a是什麽结果呢？

tenya

回复 5# tomshenhao
没有什么东西，也是空的，你看：

[root] /root
$ sysctl -a
[root] /root

   

yjh777

奇怪，什么系统？

执行下面的命令看看输出:
which sysctl
ls -l `which sysctl`
strace sysctl -a

tenya

回复 7# yjh777

$ cat /etc/issue
Red Hat Enterprise Linux Server release 6.4 (Santiago)
Kernel \r on an \m

$ which sysctl
/sbin/sysctl
[root] /root

$ ls -l `which sysctl`
-rwxr-xr-x 1 root root 0 12月  4 15:40 /sbin/sysctl
[root] /root

$ strace sysctl -a
execve("/sbin/sysctl", ["sysctl", "-a"], [/* 33 vars */]) = -1 ENOEXEC (Exec format error)
write(2, "strace: exec: Exec format error\n", 32strace: exec: Exec format error
) = 32
exit_group(1)                           = ?
+++ exited with 1 +++
[root] /root

-------------------------------------------------------------
奇怪了，我的sysctl为何变成0大小了。

   

yjh777

被人为破坏了，
    或者自己不小心执行什么操作时， 给清零了,,,

tenya

回复 9# yjh777


是的，莫名文件被清了。