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.

learn more… | top users | synonyms

-1
votes
1answer
115 views

How to check/set linux’s “security level”? [closed]

I got recommended here to check the kernel's security level—how can I print it out on a linux machine? (SLES?) If it’s set too low, how can I increase it? If I set it too high, can I ever set it ...
1
vote
1answer
1k views

Linux KVM: Troubleshooting dropped packets on a Windows Guest

virsh 0.9.10 Enterprise Linux 6.3 I have a Windows 7 guest running on the KVM host and am frequently seeing 25% loss when pinging other boxes on the same subnet. The first ping request times out, and ...
-1
votes
1answer
676 views

understanding ip route show command on linux [closed]

I have a Windows 7 PC as host.The network details of my Windows PC are as follows. IP ADDRESS - 192.168.1.70 DEFAULT GATEWAY - 192.168.1.254 I have installed Virtual Box ...
0
votes
1answer
402 views

Issues with Xen Kernel and Debian

My Xen installation has gone weird on me and I am trying to get back to normal. I overflowed the base partition and in my haste to delete unused files I think I deleted something important, so now ...
0
votes
2answers
832 views

Why does my server boot the old debian kernel?

I got a vServer with Debian installed (important because I have no idea of how Debian was installed and/or built). Output of ~# uname -r: 2.6.26-2-xen-amd64. After execution of (first some other ...
3
votes
1answer
2k views

Cannot find network subsystem in cgroup on Ubuntu 12.04 LTS

I'm trying to use cgroups to limit a process's network bandwidth, as described in this answer. However, I am unable to find the "files" they refer to. I am using Ubuntu 12.04 LTS with cgroup-bin ...
2
votes
0answers
562 views

netmap issue with wheezy linux kernel 3.2.0.4 and Intel Corporation 82599EB 10-Gigabit card

I have compiled the netmap drivers on debian wheezy with kernel 3.2.0.4 and ixgbe patched module from netmap drivers code. When I insert the modules after removing default ixgbe module I get the ...
0
votes
1answer
820 views

Centos 6.3 DRBD / OpenVZ kernel/userland issue

When I start my Centos 6.3 server's drbd service I get the following error: Starting DRBD resources: DRBD module version: 8.3.13 userland version: 8.4.2 preferably kernel and userland versions ...
0
votes
1answer
852 views

Debian Wheezy No longer booting. Freezes after setting kernel variables

My Debian (Wheezy) server has been running smoothly for a very long time with no indications of any problems. I had it running 24/7 so it was always on. The other day my power went out and when I ...
2
votes
2answers
957 views

Linux process swap usage is greater than the overall system swap usage

I have a strange problem that when I run top command it shows that some processes are using around 1.5GB of swap space but then the overall usage of the system swap is way to less to something around ...
2
votes
4answers
1k views

Linux high load with ImageMagick convert utility and server freezes (blktrack output attached)

I'm using ImageMagick to convert a JPG to TIF file, and I'm using the limit options for Imagemagick as below: /usr/bin/convert -limit memory 256 -limit map 512 subjectfile.jpg -colorspace Gray -depth ...
0
votes
1answer
518 views

CentOS server high load and server freezes

My server seems to get sudden high loads within second and when I run dmesg, following logs appear: INFO: task auditd:2185 blocked for more than 120 seconds. "echo 0 > ...
0
votes
2answers
1k views

XEN kernel shows less memory 32g

I have installed Oracle Enterprise Linux 64bit on the server with 64g of RAM. But the system detects just 32b of memory, here are the details: [root@oracle-node2 ~]# uname -a Linux ...
1
vote
1answer
358 views

Scientific Linux: soft lockup on quad opteron system

After an impressive uptime of 550 days without trouble our quad opteron system turned into a corrupted system a few days after I mounted an nfs-share from a FreeNAS-box. Ongoing sessions remained ...
0
votes
2answers
3k views

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 ...
0
votes
1answer
565 views

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 ...
1
vote
2answers
253 views

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 ...
2
votes
1answer
477 views

/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: ...
1
vote
2answers
841 views

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 ...
2
votes
1answer
3k views

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 ...
-4
votes
1answer
81 views

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
11
votes
4answers
30k views

In CentOS 6.x, how can I upgrade to Kernel 3.4?

I have a server running 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 ...
0
votes
1answer
2k views

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 ...
0
votes
1answer
6k views

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 ...
1
vote
1answer
105 views

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 ...
0
votes
1answer
2k views

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 ...
1
vote
1answer
274 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 ...
0
votes
1answer
280 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,
0
votes
1answer
183 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 ...
0
votes
1answer
80 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?
0
votes
1answer
138 views

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 ...
1
vote
2answers
5k views

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 ...
0
votes
3answers
1k views

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?
1
vote
1answer
531 views

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 ...
1
vote
1answer
188 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) ...
1
vote
1answer
371 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 ...
0
votes
1answer
325 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 ...
1
vote
2answers
7k views

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. # ...
2
votes
6answers
8k views

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 ...
0
votes
2answers
2k 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 ...
2
votes
0answers
423 views

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 ...
0
votes
1answer
1k 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 ...
2
votes
1answer
5k views

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?
0
votes
4answers
2k views

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 ...
0
votes
1answer
2k views

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 ...
-1
votes
1answer
58 views

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 ...
1
vote
2answers
222 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 ...
7
votes
0answers
2k views

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 ...
0
votes
2answers
304 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
0
votes
1answer
3k views

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 ...