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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Ubuntu 12.04 Won't Boot (hang) [on hold]

I am trying to boot my 12.04 ubuntu server, and I am getting hung on: Begin: Running /scripts/init-bottom ... done. This is in a VM on HyperV. I have tried fsck, tried going into recovery mode and ...
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1answer
23 views

Removeing ulimit from boot / init

In CentOs as from version 6 there is a by default process limit 1024 for every user i.e /etc/security/limits.d/90-nproc.conf * soft nproc 1024 I have to execute a backend ...
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5 views

Ignoring Uboot's cmdline using a pre-built one

I'm trying to compile a custom Linux kernel for my tablet, but, for debugging purposes, I have to use my custom cmdline. The U-Boot passes to the kernel his own cmdline, but it's not suitable. I can't ...
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1answer
47 views

How can I make my own linux distro? [closed]

My question is bit off-topic or may be impractical. The thing is, on the web too many material available to download customized linux distro. But what if I want to make my own linux distro ? ...
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1answer
68 views

Can't update linux kernel on VPS

I recently started using VPS from OVH: http://www.ovh.co.uk/vps/vps-classic.xml This is likely problem very specific to this one provider. My goal is to install and run Docker on it, for this I need ...
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25 views

Cannot enable NMI Watchdog on HM65 Core i5

I'm trying to enable the NMI Watchdog on Linux on an AFL-12A-HM65 touch screen with an Intel HM65 Core i5 CPU. The user manual has an implementation for DOS (real helpful) but not for Linux. There ...
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1answer
59 views

What signal is being sent to an EC2 Instance on shut down?

When you terminate an instance-store pv instance through the AWS console or the API, what "signal" does it receive so it knows it has to gracefully shut down? First guess would be ACPI, but on boot ...
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14 views

Not enough host controller resources for new device state [migrated]

I have a debian mint based system where I plug in 16 usb devices. The Kernal is: 3.11.0-12-generic After about 10 or so devices I start to experience problems with connecting new ones. There error ...
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11 views

configuring server for single process using all resources [duplicate]

i'm attempting to configure a server that will be used for data scraping using phantomjs (if you're not familiar it's a headless browser - it's webkit, controllable via javascript, without a gui ...
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36 views

Server crash : “unable to handle kernel paging request”

My fresh new Ubuntu webserver randomly crashes with the following error in the syslog. It doesn't respond anymore and I have to do a hard reboot. It happens almost one time a day. Server kernel is : ...
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24 views

__ticket_spinlock high cpu

We are having a strange problem on our Ubuntu 10.04 KVM infrastructure, where periodically, one of two vm webservers freaks out, with persistently high load, even if we restart the applications. (the ...
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1answer
51 views

What is the latest stable valid linux kernel for 3.8 version? [closed]

I want to know the latest stable kernel version of 3.8. Can any one help me out for this issue? I browsed for this issue but I didnt get the solution
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1answer
54 views

CIFS error -512 on a mount

So we have Alfresco running at work and I like to have our repository mounted via CIFS: mount /mnt/alfresco/ -v mount.cifs kernel mount options: ...
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0answers
24 views

How can I suppress rtc error messages in a CentOS 6 PV DomU?

We run a number of CentOS6 PV DomUs. Now logwatch reports afer reboot rtc-errors of this type: kernel: platform rtc_cmos: registered platform RTC device (no PNP device found) rtc_cmos: probe of ...
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2answers
50 views

Virtual Machines - Possible to Restore Replace Kernel without Rebuild?

I'm using Linux Virtual Machines (Wheezy, Linux Vserver), each with a desktop environment including Firefox. If a Virtual Machine where to be compromised (e.g., SQL injection) so the kernel is ...
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1answer
124 views

How to undo rm -rf? [closed]

How we can undo rm -rf command ? For example, I have Application folder. And I have remove it by rm -rf Application But it was my mistake and want to recovery or want that Application Folder. But ...
0
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1answer
60 views

ext4 production ready on kernel 2.6.32 (debian6)?

I've to maintain a production system on debian6 (kernel version 2.6.32). I'd like to use ext4 on a ssd disk (and generally hope to improve performance upgrading from ext3). I can't find any reference ...
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0answers
30 views

ocfs2 with pacemaker cluster, space used 5.8G

I have a corosync+pacemaker cluster with suse 11 sp2, i created 1 million of files, using this script for testing the defrag problem #!/bin/bash i=1 until (false) do for k in `seq 1 100`; do ...
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226 views

Linux Kernel complaining about TSC when selected clock source is Hyper V

We are running RHEL 6 boxes on HyperV with Windows Server 2012. On a few on our RHEL boxes, I am seeing this error in /var/log/messages kernel: Clocksource tsc unstable (delta = -62519781 ns). ...
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1answer
68 views

Linux Cannot change tx-checksumming

On a Linux 3.2 kernel: Linux 3.2.0-4-686-pae #1 SMP Debian 3.2.46-1+deb7u1 i686 GNU/Linux on VmWare, i get checksum errors on ipv6 tcp packets. So I can ping6, but not connect by ipv6 to ssh, smtp, ...
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1answer
39 views

Make a bridge with two ports behave like a veth pair

I have a linux bridge with two ports, namely p0 and p1, and I would like to modify the bridge behavior so that every frame showing up in one port is relayed to the other port and viceversa, i.e. the ...
0
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1answer
86 views

LVM RAID 1 for root

I have LVM RAID 1 (not mdadm RAID 1, but exactly LVM2 RAID 1) for my root partition. I would like to make my system boot without either of the HDDs where the underlying PVs of the root LVM partition ...
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2answers
48 views

find out which memory pages are owned by kernel

I can obtain a wonderful memory map of all processes with the Linux command pmap $(ps -A | awk '{print $1}'|grep -v PID) | sort | grep \^0 It looks like ... 00007fd6dbf45000 4K rw--- ...
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43 views

ext3 option on error doesn't work

I have a redhat server 5.8 with ext3 on top of lvm, i noticed ext3 has setting "Errors behavior: Continue" in the fs super block, from the man page of mount command i readed this ...
4
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1answer
124 views

Linux: echo 3 > /proc/sys/vm/drop_caches takes hours to complete

I have a Thecus N8900 NAS, which is a Linux based file server, providing files via NFS to six clients. For some reason that Thecus support has yet to explain, it runs a script that checks ...
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1answer
97 views

esxi 5 VMKernel and linux driver compatability mode [closed]

Many peoples around the web say, the esxi 5 kernel isn't based on linux kernel, but in the same times they say "ESX(i) includes a Linux driver compatability mode (drivers still have to be compiled ...
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1answer
69 views

12.04 Migration Process time delay

We have an issue in our server that is the migration process in taking time and also the load in the server is getting high due to that. No LSB modules are available. Distributor ID: Ubuntu ...
10
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2answers
210 views

Linux kernel detecting wrong processor frequency

After a cold boot of a 6.0.8 Debian server (HP ProLiant), ntpd played havoc with system time: offset and jitter with respect to the usual and reliable reference time servers growing without limit. ...
2
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1answer
48 views

Linux Kernel setup: is it good idea to enable everything in Cryptographic API?

There are several implementations for some algorithms, which use CPU instructions which may or may not be available on current system. Is it good idea to just enable (in kernel, not as modules) all of ...
0
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1answer
72 views

What are Linux shared memory 'segments' vs. 'pages'?

The Linux kernel docs say: shmall: This parameter sets the total amount of shared memory pages that can be used system wide. Hence, SHMALL should always be at least ...
3
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1answer
44 views

Linux kernel thread dependency graph?

I'm trying to benchmark a system with a software RAID-10 volume, backed by Fusion IO cards. Is it possible to display a Linux kernel thread dependency graph? I would like to know how all the ...
3
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1answer
55 views

How to force logging all terminal actions on Ubuntu 12.04 server?

I believe my server has just got compromised interactively. As this server will go to thrash anyway, I wonder if I can get a better insight of what the villain is doing by forcing logging of all ...
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101 views

Should I set rto_min for a route inside data center?

We have a few dedicated server rented in a data center with debian 7, kernel 3.2. We use one of those servers as a database server. The network between our application server and database server is ...
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125 views

KVM - task foo:1234 blocked for more than 120 seconds - howto change task scheduler

I recently installed a new Debian Wheezy server with KVM (the "KVM Host") then installed a Debian VM on the KVM (the "VM"), and got very bad performance on the VM. Looking through dmesg on the VM, I ...
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219 views

linux initcwnd and initrwnd via /etc/sysctl.conf

Folks, As we know, the 3.x kernels have higher TCP default connection values, such as initcwnd and initrwnd. For 2.x friends, is there a way to set these in /etc/sysctl.conf instead of the ip route ...
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1answer
89 views

What is the purpose of /proc/config.gz

Please what is the purpose of the /proc/config.gz file in my Linux server filesystem? Is it some backup file, or it is an updated file by the Linux system? Can I change it?
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3answers
273 views

High CPU usage in random IP/Port UDP DDoS

I have been getting these UDP floods with random IPs and ports. randomip:randomport -> myip:randomport 0 byte payload For some reason it is using a lot of CPU. Here is the results of perf top -e ...
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2answers
288 views

Can't resolve issue: iptables: No chain/target/match by that name

So I am trying to setup shorewall firewall on my linux vps. The vps is running ubuntu 12.10. When I type $ shorewall check I get this error. iptables: No chain/target/match by that name. ERROR: ...
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2answers
230 views

/var/log/messages showing lots of CE Err=0x2000 even on unused banks (slots)

I recently had to upgrade an old server (HP ML350G5) with used FBDIMM DDR2 RAM (could not get new ones where I live). After rebooting /var/log/messages has been plagued with CE Err=0x2000 errors but ...
1
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1answer
66 views

Fixed TCP payload Size [closed]

I have an aplication that need to have a fixed (516 byes) payload size in the TCP packet. The application itself can't be modified to adjust it settings, therefore i need to tune the TCP Buffer Size ...
5
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2answers
452 views

MySQL 5.5 degraded performance in linux kernel 3.2 compared to 2.6

Our database servers (mainly based on the Debian stable packages (=currently Wheezy) seem to have about 4 times more load for the same workload in kernel 3.2.0-4-amd64 then in it's previous ...
1
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0answers
112 views

Capturing on loopback device on Ubuntu LTS: 15 Mbit of traffic and “x dropped packets”

I am trying to capture about 15 Mbit of traffic on the loopback device on Ubuntu LTS using tcpdump, and I am seeing dropped packets. The CPU is a freaking i7, and i have yet to see CPU usage go above ...
0
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1answer
44 views

forcing linux kernel 3 to recognize cdrom as hdX

I have a problem with older version of anaconda linux installer. I have upgraded kernel in my distro, however, when this anaconda boot with this 3.4.52 kernel, can NOT find cdrom. As far as I ...
3
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1answer
112 views

Linux (non-transparent) per-process hugepage accounting

I've recently converted some java apps to run with linux manually-configured hugepages. I've got about 10 tomcats running on a system and I am interested in knowing how much memory each one is using. ...
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277 views

Kernel panic - not syncing: VFS: Unable to mount root

I uploaded a centos 6.2 VMDK to s3 and then converted it to volume using ec2 import volume. Then i took the snapshot of the volume and deleted it.Now I am trying to create a instance from the snapshot ...
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1answer
299 views

What is required to activate cgroups in Linux

I have a Debian squeeze kernel (linux-image-2.6.32-5-openvz-amd64) which according to the Doku should support cgroups. When I look into the kernel configuration, it does (or is some other kernel ...
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1answer
344 views

please explain my fio results - is O_SYNC|O_DIRECT misbehaving on linux?

I'm going mad over figuring out what the problem could be with one of our storage boxes. With a simple fio script I'm testing random writes using bs=1M and direct=1. The SSD is a Samsung 840pro ...
0
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1answer
54 views

Debian squeeze kernel update under Security Updates

Can someone explain what squeeze1 and squeeze3 designate at the end of a kernel name? For instance 2.6.32-48squeeze3 is showing up under Security Updates in Aptitude.
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147 views

Kernel update on Xen CentOS

Running a "yum update", CentOS try to install a new kernel. However, I get this: Installing : kernel-2.6.32-358.6.2.el6.x86_64 1/1 grubby fatal error: unable to find a suitable template ...
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84 views

linux kernel configuration to filter multicast traffic based on interface

I have two virtual interfaces (eth0.2, eth0.3) in my PC. I am sending multicast data from eth0.2 to eth0.2. Multicast data is received in eth0.2 but also received in eth0.3, the other virtual ...