The Linux kernel is the operating system kernel used by the Linux family of Unix-like operating systems. It is one of the most prominent examples of free and open source software.

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Xen Paravirtualized Guest - Invalid Kernel

I have set up xen on ubuntu server 12.04 LTS. I have tried installing a guest to an lvm I created called xen-lvm The virt-install script: sudo virt-install \ --name client2-ubuntu-server \ --ram 512 ...
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CentOS 6.3 with kernel-ml(3.7.1-2.el6.elrepo.x86_64) - No Console Output

I installed kernel-ml(3.7.1-2.el6.elrepo.x86_64) from elrepo on CentOS 6.3, and everything is working fine, except that I see nothing on the console and can't interact with it. I can SSH to the ...
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using Linux as a bootloader?

I have an embedded device with a SPI connected flash. Basically this means the device boots its bootloader and Linux kernel from a small flash part. As the device boots, but before the root ...
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/proc/<pid>/stat children CPU time

I've been running the following command on my linux box: watch -d -n 1 "cat /proc/19866/stat" The pid above is a pid of Nginx's master process - I would expect the following fields to be changing: ...
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Server freezes and suddenly load going very high

I'm on CentOS 5.7 and I get server freezes quite a lot and the logs show the following output: Dec 26 18:33:51 server kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this ...
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Where are the acpiphp and pci_hotplug kernel modules for KVM hotplug in CentOS/RHEL?

On the this how-to I read the following: I loaded the following modules to get pci hotplug working: acpiphp pci_hotplug You can either add these to your distro's module list to ...
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Which Flavour of Linux comes with default kernel 3.4? [closed]

I was using centos but came to know it has restrictions to upgrade kernel version so looking for any other flavour with default 3.4 kernel version please suggest
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In CentOS 6.x, how can I upgrade to Kernel 3.4?

I have a server with CentOS 6.2 with kernel version 2.6.32, but I need to increase my application Performance. The Kernel Version 3.4 has x32abi which can improve the performance so i want to upgrade ...
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How can I confirm if my CentOS server supports multiple CPUs?

CentOS 5.8 | VMWare I've got a server running a hardened version of CentOS 5.8. I've been using a single CPU on it and am planning to add another (via vmware). When I run uname, I see SMP which ...
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CentOS 6.3 task blocked for more than 120 seconds

Recently have been getting Zabbix alerts about our mail system being unavailable, the uptime on the machine is 30+ days. I've been tracing the Zabbix logs and it looks like the communication between ...
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Size of modules within initrd

I am currently trying to manually replace the kernel within ubuntu-core on an embedded device with a custom kernel. However when I try to update the initrd my initrd becomes much bigger. Here is what ...
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How to stop a infinite running process(ztail) started by a ssh session after that session is closed

I have a peculiar problem. My server supports multiple ssh session simultaneously, so that multiple admins can manage it simultaneously. We have a command which calls ztail to show the compressed log ...
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260 views

Nonstandard kernel on CentOS

CentOS/RH is very widely supported as a server distro, but it mounts a somewhat older kernels. For example now it runs kernel 2.6, while 3.6 is already out. I found several tutorials about upgrading ...
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233 views

what is occupying linux low memory

How can I find what is occupying my low memory on 32 bit Linux OS? cat /proc/meminfo |grep Low LowTotal: 812908 kB LowFree: 43340 kB Regards,
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1answer
139 views

yum security update - message indicating kernel version not up to date

Running yum --security check-update returns this message: Security: kernel-3.x.x-x.63 is an installed security update Security: kernel-3.x.x-x.29 is the currently running version I already ran the ...
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1answer
75 views

CentOS: Prevent the kernel from updating?

I have installed a non-rpm custom kernel. I have a cron job which does yum -y update in the background. Is it sufficent to remove the kernel packages to prevent them from being updated?
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Installing a custom 'non-rpm' kernel in CentOS 6

I've built a custom kernel using kernel.org, it has no .rpm file. How do I manually: Install the Modules to /lib/modules (make moduleinstall or something?) Make the initial ramdisk Update grub I ...
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Centos kernel .config file. Where can I find it?

I am rebuilding a custom kernel. I am on Windows, what is the quickest way to grab the .config file for the CentOS RHEL linux kernel (for make oldconfig). I can't find it preinstalled in the Linux ...
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Is Linux 3 kernel series compatible with CentOS 6?

For proper TPROXY support I was looking for a STABLE Linux kernel of at least version 3.2.30. Do they want us to upgrade to version 3 of the kernel? And is that compatible with CentOS 6?
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Is it possible to disable or tune filesystem cache sharing for OpenVZ?

For OpenVZ, an implementation of container-based virtualization, it seems that host and all guests are sharing the filesystem cache. This sounds paradoxical when talking about virtualization, but this ...
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173 views

How do I correct the kernel version loaded by Grub2 in Ubuntu 12.04

I have a linux vps running Ubuntu 12.04 and when I run uname-r it replies: paul@webforms:~$ uname -r 2.6.32.33-kvm-i386-20111128-dirty paul@webforms:~$ sudo grub-install -v grub-install (GRUB) ...
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310 views

How can I get APT to “ignore” a package?

I am running a VPS using Debian unstable with this kernel version: 2.6.32-274.7.1.el5.028stab095.1 I just upgraded my packages and for some odd reason APT wants me to install ...
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222 views

How to disable specific CPUs in Linux 2.6.26.2

I have an old machine running Linux kernel 2.6.26.2 which is behaving oddly. I suspect ONE of the CPUs is possibly heating faster than the other. I want to run some tests with specific CPUs/cores ...
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Can't install kernel-uek-headers for currently running kernel

I have just created a VM in VMWare and installed a minimal install of Oracle Enterprise Linux 6.3. # cat /etc/oracle-release Oracle Linux Server release 6.3 It is running with the UEK kernel. # ...
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Debian on Hyper-V

I installed Debian with kernel 2.6.32-5-686 on a Hyper-V virtual machine. I had to add a legacy network card. I follow this tutorial ...
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Kernel panic - not syncing - Attempted to kill init

I am using Linux 2.6.32-33-server #70-Ubuntu 10.04.3 as Data-Nodes and Name-Node in my Hadoop cluster, but one of my data node is down since morning. When i restarted that particular system it ...
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KVM host kernel configuration for best performance

I'm currently building a kernel for my server, which should serve for hosting virtual machines using KVM. There are a few kernel configuration options that are already described in the KVM-Wiki. The ...
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1answer
997 views

kernel + libc6 issue upgrading to squeeze

I used to run Debian testing, and I haven't upgraded or dist-upgraded for about 2 years. Yesterday I made the mistake of trying that... it didn't work (I don't remember the exact error messages), so I ...
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1answer
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Limit the number of max threads used by a process in linux kernel

I think I have found something that I need from the Linux kernel that is not currently implemented. I need a way to set a max thread limit per process. Is this possible?
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How to tune Linux kernel to withstand DDoS? (HAProxy)

Please do not reply with "this is not possible", as it's waste of time. I am developing cloud appliance and I have a valid reason to protect this layer against DDoS, and there are few companies doing ...
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NFS4: rpc.idmapd or nfs.idmap upcall?

https://www.kernel.org/doc/Documentation/filesystems/nfs/idmapper.txt states: The file /etc/request-key.conf will need to be modified so /sbin/request-key can direct the upcall. The following line ...
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RHEL4 - 2.6.9-55 TO UPDATE 8 [closed]

I am having clearcase 7.0.1 application running on RHEL 4.0 (Paid & Unregistered)with the kernel version 2.6.9-55. When we ask the support redhat they said its not possiable because its not ...
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linux sever interfaces automation

I am using a CentOS server which has about 6 active interfaces with different IPs, I'd want to automatically bring down all the interfaces when any one of the 6 interfaces is down. Is there a way this ...
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Multithreading with multi-queue NIC on SMP system [closed]

How are packets scheduled from network interface queues to CPUs, then onwards to threads for processing? What needs to be considered when it comes to how packets are hashed across queues, hardware ...
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linux virtual server with io issues - deadline vs noop elevator

I have a Linux virtual server experiencing IO issues from MySQL. Would using the deadline io elevator possibly be preferable to noop in this case? Thanks
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An oom killer that I cannot explain

I am not able to understand why would kernel issue this oom killer when I see enough memory is available: I say enough memory is available after looking at Normal DMA Normal free lines This is an ...
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How do I set the default kernel parameters in CentOS for all existing and future kernels?

I'd like to remove the rhgb and quiet kernel parameters which are used by default when the kernel is booted in CentOS 6, but I want this to apply to all currently installed kernels as well as any ...
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1answer
364 views

Adding Linux kernel command line parameters

I would like to increase the size of the vmalloc region from the default value, and pass vmalloc= as a command line parameter while booting. I am booting a uImage. In which file do I need to add the ...
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Activate Passive Arp learning

I want to enable my linux-kernel to passively listen (learn) the arp request broadcasted in the lan segment (arp request in the network not destined for me). Is there any configuration available?
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Xen dom0 crashed

Lots of questions this week, I got this error on dom0, then the server crashed (according to /var/log/messages): Jun 22 10:02:09 453 dhcpd: DHCPACK to xx.xxx.xxx.xx (xx:xx:xx:xx:xx:xx) via eth0 Jun ...
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1answer
113 views

Making directories visible only by owners

I am in the process of creating a secured shared hosting and, between the hosting features, I want to give SSH access. I've already chrooted the users via SSH, FTP and PHP (using PHP-FPM), and would ...
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What are some options for acquiring a free realtime Linux distribution? [closed]

By realtime I mean something that can help with fast network I/O; Low-latency and high-throughput.
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Compiling linux kernel - `make install` asks for LILO. Now what?

So I am following this guide to compile my custom kernel - http://library.linode.com/linode-platform/custom-instances/pv-grub-custom-compiled-kernel#sph_compile-and-install-the-kernel So far so good, ...
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1answer
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Do i have to install vmware tools on ubuntu server

its a bit silly Question, I was thinking since i have some spear HW to install ESXi free edition and allow some external users to use prebuild ubuntu 10.04 servers. since with kernel updates etc etc ...
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1000 HZ linux kernel necessary if I have tickless and high resolution timer?

I am trying to improve performance on my server. I have a few processes that need low jitter (less than 10ms variance). I have a load average of 4 maximum on an i7-920 (4 physical cores, 8 with HT). ...
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Linux Kernel Versioning: Debian Sid vs Ubuntu Precise

I have setup two machines: On one machine I have installed Ubuntu Precise 12.04 beta and dist-upgraded to the latest packages. On the other machine I have installed Debian Sid Unstable and ...
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tc u32 — how to match L2 protocols in recent kernels?

I have a nice shaper, with hashed filtering, built at a linux bridge. In short, br0 connects external and internal physical interfaces, VLAN tagged packets are bridged "transparently" (I mean, no VLAN ...
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How can I tell the kernel to free cached memory during memory allocation request instead of the OOM killer terminating the application

I am running Ubuntu 10.04 with the below kernel version Linux ip-10-0-1-119 2.6.32-343-ec2 #45-Ubuntu SMP Tue Feb 14 18:18:17 UTC 2012 x86_64 GNU/Linux The memory status shows that the cache is ...
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Kernel panic on Linux Red Hat server

Linux server has been running fine, no updates installed recently, but out of the blue this morning the server stopped responding. I went to check it and it was saying there is a problem with the ...
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Effects of configuring vm.overcommit_memory

My VPS web server running on CentOS 5.4 (Linux kernel 2.6.16.33-xenU) irregularly (like once a month give or take a few weeks) becomes unresponsive due to oom-killer kicking in. Monitoring of the ...