Tagged Questions

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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0
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1answer
92 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
642 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
256 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
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1answer
232 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
138 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
73 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
125 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 ...
0
votes
2answers
3k 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 ...
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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
434 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
172 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
305 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
216 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
5k 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
4answers
6k 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
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 ...
2
votes
0answers
371 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
969 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
2k 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?
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votes
4answers
1k 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
1k 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
50 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
137 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 ...
5
votes
0answers
1k 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
236 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
2k 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 ...
6
votes
2answers
9k views

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 ...
0
votes
1answer
358 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 ...
-1
votes
2answers
267 views

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?
0
votes
1answer
222 views

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 ...
1
vote
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 ...
-4
votes
1answer
1k views

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.
0
votes
2answers
1k views

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, ...
2
votes
1answer
241 views

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 ...
9
votes
3answers
4k views

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). ...
8
votes
2answers
797 views

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 ...
10
votes
4answers
2k views

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 ...
3
votes
1answer
200 views

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 ...
1
vote
4answers
4k views

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 ...
12
votes
2answers
9k views

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 ...
3
votes
1answer
185 views

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 ...
7
votes
5answers
829 views

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 ...
0
votes
1answer
261 views

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 ...
3
votes
1answer
435 views

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 ...
0
votes
2answers
632 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] ...
6
votes
2answers
602 views

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 ...
0
votes
1answer
234 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 ...
8
votes
1answer
6k views

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 ...
0
votes
2answers
756 views

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 ...
0
votes
1answer
223 views

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 ...