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Questions tagged [sysctl]

The sysctl is a Unix interface used to modify variables that the kernel uses to determine behavior. There are two ways to work with sysctl: by directly reading and modifying files in /proc/sys and by using the sysctl program supplied with most distributions. The regedit interface is the closest parallel for Windows.

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Solving Redis warnings on overcommit_memory and Transparent Huge Pages for Ubuntu 16.04 on EC2

On a fresh Ubuntu 16.04 EC2 instance the warnings appear like so: WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run…
legel
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Cannot run sysctl command in Dockerfile

I'm trying to make my first dockerfile(I'm new to this), and I need the system to run the command sysctl -w kernel.randomize_va_space=0 (its an lab env.), but I get the error: sysctl: setting key "kernel.randomize_va_space": Read-only file …
neorus
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Refresh net.core.somaxcomm (or any sysctl property) for docker containers

I am trying to change net.core.somaxconn for docker container to be able to have larger queue of requests for my web application. On OS, outside docker, I first modify the property successfully: $ cat /proc/sys/net/core/somaxconn 128 $ sudo sysctl…
Tuukka Mustonen
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Disable and re-enable address space layout randomization only for myself

I would like to disable address space layout randomization (ASLR) on my system (Ubuntu Gnu/Linux 2.6.32-41-server), but, if I use sysctl -w kernel.randomize_va_space=0 the change would affect all users on the system, I presume. (Is this true?) …
Amittai Aviram
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Permanent fix to tail: cannot watch `log/development.log': No space left on device

I've been using Ubuntu 11.10 for a little over a week now. But after some time I encountered this error(the one in the title) when Im trying to access the log in my RoR project. I found a fix which is by pasting this in the terminal: sudo sysctl…
Normz
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Need to "calculate" optimum ulimit and fs.file-max values according to my own server needs

Need to "calculate" optimum ulimit and fs.file-max values according to my own server needs. Please do not conflict with "how to set those limits in various Linux distros" questions. I am asking: Is there any good guide to explain in detail,…
Kunthar
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Detect which app is currently running on iOS using sysctl

I have currently implemented a simple activity monitor to watch all running processes on iOS. To retrieve a list of all running processes, I do this: size_t size; struct kinfo_proc *procs = NULL; int status; NSMutableArray *killedProcesses =…
hackerdiehack
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Invalid argument" setting key "net.core.somaxconn"

I tried setting Linux kernel. After editing /etc/sysctl.conf and executing the sysctl -p it shows error Invalid argument" setting key "net.core.somaxconn" Linux distribution: Ubuntu 12.04.4 LTS, x86_64, 3.2.0-60-generic $ cat…
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Can I use `sysctl` to retrieve a process list with the user?

I am in need of a way to retrieve all running processes for all users on a Mac (using Cocoa). I found an implementation to retrieve the process using sysctl, but I also need the running user. This is a snipping of what I've got to get the process…
bugfixr
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What does '|' mean in file /proc/sys/kernel/core_pattern?

$ cat /proc/sys/kernel/core_pattern |/usr/share/apport/apport %p %s %c %d %P What does '|' mean in file /proc/sys/kernel/core_pattern?
Ren
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Monitoring network usage excluding local traffic

I am working on an app that monitors network usage. However I noticed many ways to do this does not allow exclusion of local traffic (say, Time Machine). I am looking for a way to exclude local traffic, and only monitors usage that goes directly…
koo
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How to get maximum TCP Receive/Send window in MAC OS X?

How to get maximum TCP Receive/Send window in MAC OS X? There are two ctl in Linux. /proc/sys/net/core/rmem_max - Maximum TCP Receive Window (NET_CORE_RMEM_MAX) /proc/sys/net/core/wmem_max - Maximum TCP Send Window (NET_CORE_WMEM_MAX) but i…
Vlad
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Does anybody know equivalent for NETLINK Sockets API for MAC OS X?

Does anybody know equivalent for NETLINK Sockets API for MAC OS X ? I am trying to port Linux application to MAC OS X and I couldn’t find anything similar in MACOS. I need to provide asynchronous access to the network adapter in my…
Vlad
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Linux parameters sysctl list of the Linux kernel and its explanation

Does anyone know where I can find a parameters list of sysctl for the linux kernel and its explanation? I've searched for it and have found nothing. I looked in the kernel headers too with the same result.
Emilio Granados
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iOS cpu usage for each process using sysctl()?

Is there a way to get cpu usage for each process using sysctl() ? I'm trying to find a way to detect the launch of a specific application. It seems there's no way to get foreground running app information. So I guess if I can monitor cpu usage for…
Rukshan
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