Virtual Machine running on VMWare workstation 9.2
os : RHEL 5.8
RAM : 2.5GB
Swap : 2.6gb
CPU : 1 virtual CPU
Surprizingly I couldn't find much from googling on What exactly does Kernel parameters do ?
I was under the impression that kernel parameters just set the limits/maximum for a certain resources in the server.
To install Oracle RDBMS in my Linux VM, i set /etc/sysctl.conf as shown below . I found these settings from google.
I restarted the VM after after editing /etc/sysctl.conf like above. But the Linux VM was hanging at startup. It took around 1 hour for the VM to actually come up and it was very slow. So, i reverted /etc/sysctl.conf to the original file.
Why was the VM hanging at startup ?
Has it got anything to do with the kernel.shmmax value? But I am just setting a maximum possible value here. Right ?
Good Day
Please couls somebody tell me how to display Configurable Kernel parameters from the command line. I am able to do it from SAM,but would like to dump the command line output to a text file so I can email it off to HP.
Kind Regards
Shawn (1 Reply)
Hi all,
I'm at SCO UNIXWARE 7.1.1, my system's memory is larger than dump device, I have found one kernel tunable parameter at SCO website ie SYSDUMP_SELECTIVE which tells me that if set to 1 system will dump only kernel mapped memory, but I'm not sure how to configure this parameter. As well... (2 Replies)
I want to change some kernel parameters in HP-UX11, to do with Oracle upgrade/install.
I know this is done using SAM. I am told SAM will not let you enter values outside the allowable range. Could anyone tell me if they have experienced anything different?
In Solaris, I would copy the... (2 Replies)
Hello all, Can anyone tell me the command line I can use to look at the following Kernel parameters:
nfile
maxfile
maxfile_lim
I'm using the Reflection manager connection to my Unix box so I can't use SAM. (3 Replies)
I've been trying to find out the following parameters of our Unix box:
==>OS version
==> patch level
and the following kernel parameters
=>maxfiles_lim
=>maxvgs
=>nproc
=>msgmni
=>ncsize
=>nfile
Could someone help me how would I find the above(commands)?
Thanks,
Bhagat (1 Reply)
Hi,
I'm new to HP-UX. i'm working on HP-UX 11.31 ia64 for testing our product
i could able to change the kernel parameter values and i need to add the following parameters to the parameters list
semmap = 258
nfile = 2048
msgseg = 7168
msgssz = 32
maxusers = 60
msgmap = 258
msgmax =... (4 Replies)
Hi gurus
Could anybody tell me which file is read by kernel to set its default system kernal parameters values in solaris. Here I am not taking about /etc/system file which is used to load kernal modules or to change any default system kernal parameter value
Is it /dev/kmem file or something... (1 Reply)
Hi,
if I install a module with specific parameter, will this parameters applied next time system boots?
for exampe, I want to disable InterruptThrottleRate
modprobe e1000e InterruptThrottleRate=0
Is this parameter apllied only for this run, or this module will always use this parameter when... (2 Replies)
Dear All,
I want to check whether all essential kernel parameters are installed in my Solaris 10 System. Is there any way to find it.
And also how to tune it.
Kindly help.
Thanks and Regards
Rj (8 Replies)
Dear All,
I have weblogic Portal Installed in the Server solaris 10.
How can i verify whether all the kernel parameters are available for this Software and also another question is
How to crosscheck a server ( Solaris 10 Sparc ) whether it has all the required kernel parameters.
... (2 Replies)
Discussion started by: jegaraman
2 Replies
LEARN ABOUT PHP
sysctl.d
SYSCTL.D(5) sysctl.d SYSCTL.D(5)NAME
sysctl.d - Configure kernel parameters at boot
SYNOPSIS
/etc/sysctl.d/*.conf
/run/sysctl.d/*.conf
/usr/lib/sysctl.d/*.conf
DESCRIPTION
At boot, systemd-sysctl.service(8) reads configuration files from the above directories to configure sysctl(8) kernel parameters.
CONFIGURATION FORMAT
The configuration files contain a list of variable assignments, separated by newlines. Empty lines and lines whose first non-whitespace
character is "#" or ";" are ignored.
Note that either "/" or "." may be used as separators within sysctl variable names. If the first separator is a slash, remaining slashes
and dots are left intact. If the first separator is a dot, dots and slashes are interchanged. "kernel.domainname=foo" and
"kernel/domainname=foo" are equivalent and will cause "foo" to be written to /proc/sys/kernel/domainname. Either
"net.ipv4.conf.enp3s0/200.forwarding" or "net/ipv4/conf/enp3s0.200/forwarding" may be used to refer to
/proc/sys/net/ipv4/conf/enp3s0.200/forwarding.
The settings configured with sysctl.d files will be applied early on boot. The network interface-specific options will also be applied
individually for each network interface as it shows up in the system. (More specifically, net.ipv4.conf.*, net.ipv6.conf.*,
net.ipv4.neigh.* and net.ipv6.neigh.*).
Many sysctl parameters only become available when certain kernel modules are loaded. Modules are usually loaded on demand, e.g. when
certain hardware is plugged in or network brought up. This means that systemd-sysctl.service(8) which runs during early boot will not
configure such parameters if they become available after it has run. To set such parameters, it is recommended to add an udev(7) rule to
set those parameters when they become available. Alternatively, a slightly simpler and less efficient option is to add the module to
modules-load.d(5), causing it to be loaded statically before sysctl settings are applied (see example below).
CONFIGURATION DIRECTORIES AND PRECEDENCE
Configuration files are read from directories in /etc/, /run/, and /lib/, in order of precedence. Each configuration file in these
configuration directories shall be named in the style of filename.conf. Files in /etc/ override files with the same name in /run/ and
/lib/. Files in /run/ override files with the same name in /lib/.
Packages should install their configuration files in /lib/. Files in /etc/ are reserved for the local administrator, who may use this logic
to override the configuration files installed by vendor packages. All configuration files are sorted by their filename in lexicographic
order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the
lexicographically latest name will take precedence. It is recommended to prefix all filenames with a two-digit number and a dash, to
simplify the ordering of the files.
If the administrator wants to disable a configuration file supplied by the vendor, the recommended way is to place a symlink to /dev/null
in the configuration directory in /etc/, with the same filename as the vendor configuration file. If the vendor configuration file is
included in the initrd image, the image has to be regenerated.
EXAMPLES
Example 1. Set kernel YP domain name
/etc/sysctl.d/domain-name.conf:
kernel.domainname=example.com
Example 2. Apply settings available only when a certain module is loaded (method one)
/etc/udev/rules.d/99-bridge.rules:
ACTION=="add", SUBSYSTEM=="module", KERNEL=="br_netfilter",
RUN+="/lib/systemd/systemd-sysctl --prefix=/net/bridge"
/etc/sysctl.d/bridge.conf:
net.bridge.bridge-nf-call-ip6tables = 0
net.bridge.bridge-nf-call-iptables = 0
net.bridge.bridge-nf-call-arptables = 0
This method applies settings when the module is loaded. Please note that, unless the br_netfilter module is loaded, bridged packets will
not be filtered by Netfilter (starting with kernel 3.18), so simply not loading the module is sufficient to avoid filtering.
Example 3. Apply settings available only when a certain module is loaded (method two)
/etc/modules-load.d/bridge.conf:
br_netfilter
/etc/sysctl.d/bridge.conf:
net.bridge.bridge-nf-call-ip6tables = 0
net.bridge.bridge-nf-call-iptables = 0
net.bridge.bridge-nf-call-arptables = 0
This method forces the module to be always loaded. Please note that, unless the br_netfilter module is loaded, bridged packets will not be
filtered with Netfilter (starting with kernel 3.18), so simply not loading the module is sufficient to avoid filtering.
SEE ALSO systemd(1), systemd-sysctl.service(8), systemd-delta(1), sysctl(8), sysctl.conf(5), modprobe(8)systemd 237SYSCTL.D(5)