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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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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177 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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331 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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261 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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1k views

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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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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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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2answers
177 views

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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269 views

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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1answer
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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
400 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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1answer
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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
117 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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5answers
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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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1answer
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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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4answers
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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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2answers
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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 ...
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1answer
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What is the interrest of playing with drop_caches?

I've seen sysadmins playing with /proc/sys/vm/drop_caches (echo 3 into this file from a cron) in order to free caches. Is there a real interrest in doing this? Aren't the clean caches reclaimed when ...
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Convey multicast (to another LAN) through WAN disabling multicast

My Server and Client softwares run both on Linux. The Server broadcasts multicast, the Client listens multicast. My Client has to migrate to another site, and unfortunately multicast is not allowed ...
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1answer
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linux kernel soft lock nagios

I've had this happen a few times in the past few days, anyone have any idea what might be causing this? Looks related to nagios/smp/memory management. Seems to be recurring every 24hrs or so. This is ...
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1answer
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Installed 2TB disk in ubuntu server, dmesg reports it as 9444732965540666 MB

I've have an ageing Linux server running on Dell PowerEdge hardware, with a SAS 5IR RAID controller. It has a pair of SAS 146Gb disks in a RAID 1 configuration that has the OS and other software. I ...
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2answers
665 views

Weird [migration/x/x] behaviour

On one of my servers there are 173 [migration] processes listed in ps aux. It has 8 processors so there are the regular 1 per processor right at the top of the list. PID COMMAND 2 [migration/0/0] ...
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2answers
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Kernel updates without rebooting

Similar to some of the topics touched on in this question, Rebooting servers for kernel updates, I was curious if there was a way in which one could apply kernel updates to the system without ...
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1answer
300 views

adding new scheduling policy to the kernel

i'm working on a redhat 8 linux and i want to add new policy for scheduling the processes , could you help me with : 1) where to define the new policy 2) how does the process of assigning a policy for ...
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1answer
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Flush processes consume too much of CPU

The Server is EC2 Instance, it stands for saving files to NAS (NFS) from HTTPD. The processes like flush-0:32 consume over %90 of CPU and load average: 65.50, 64.02, 66.59. According the graph, it's ...
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2answers
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Linux kernel upgrade broke : How do I remove the kernel that broke it all?

I just upgraded an Ubuntu 10.04 (Server Edition) to '2.6.32-36'. However, after doing that upgrade the server would not longer start and GRUB tells me that it is unable to read the header. I rebooted ...
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1answer
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Linux Kernel Usb Printer Device Class driver

I am trying to update the CUPS daemon on my QNAP NAS, which runs a flavor of *nix. The entire OS system is loaded on a RAMDISK when the NAS boots so I've come up with a script that runs at start-up ...
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2answers
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Time drift in Cloud Server - need to mainpulate GRUB config

We are hosting a VPS on a popular host and are experiencing a regular time drift of several minutes a day forward (approx 7). Linux Kernel: 2.6.18-164.11.1.el5 GNU/Linux Distro: CentOS release 5.4 ...
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1answer
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Can't find the pdflush thread?

I just found out there's no pdflush on my Linux, v2.6.38. But when I do a ps uax | grep flush It shows: root 269 0.1 0.0 0 0 ? S 13:05 0:04 [flush-8:0] My kernel is: ...
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2answers
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ESXi :: vmxnet3 vNIC and Linux kernel errors

a long shot, but figured I'd give here a try (no solution on VMware community forum). In a Linux guest (CentOS 5.7 64-bit) with vmxnet3 vNIC we are getting a few hundred kernel errors per day on ...
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how do i set hard and soft file limits for a non-root user at boot?

I have a xen HVM vps and I'm trying to raise the hard and soft file limits for nobody at boot time. I'm using Ubuntu 10.04.3 and inside /etc/security/limits.conf I have: nobody soft nofile ...
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Does Linux support IPsec service out of the box?

As per subject. I have heard of default IPsec support on later versions of Linux kernel (without need to recompile or install special packages) but maybe it's a rumour? Interested in both VPN ...
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Debian squeeze kernel backports upgrade - moving forward?

It was suggested to update my Debian Squeeze kernel to something more recent. We chose 2.6.38 and used Debian Backports to install linux-image-2.6.38-bpo.2-amd64 following these instructions ...
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1answer
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Linux kernel crash - any ideas?

Been getting these runaway conditions on a lightly loaded vps (debian squeeze kernel 2.6.38-bpo.2-amd64, 2GB, SSD) - top load is nothing , then jumps to 30.0 & everything grinds to a halt. I'm ...
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1answer
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Need rpcsec_gss_krb5 and Linux kernel 2.6.35+ on EC2

I am trying to do Kerberos-auth:d NFS4 on EC2. In order to do this, it seems one wants a kernel at least 2.6.35 in order to get decent encryption algos. The distro I could find that provides this is ...
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Where to download the latest 2.4.x Linux kernel while kernel.org is down?

I need to run the pre-paleolithic (10 years old!) SuSE 7.3 under VirtualBox. (Don't ask. I just do, ok?) I managed to successfully install it. It boots. It recognized the virtual NIC (pcnet32 module) ...