In computing, the kernel is the main component of most computer operating systems; it is a bridge between applications and the actual data processing done at the hardware level. The kernel's responsibilities include managing the system's resources (the communication between hardware and software ...

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14 views

Debian/Installer Preseed Remove Post Install Kernel Options + Multi NIC Preseed Tip

In light of recent automation trends, I would like to be able to fully automate an install of Ubuntu. My my first problem was auto selection of the bootif with multiple NICs break Ubuntu/Debians ...
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0answers
23 views

SSH traffic forwarding in Linux kernel [closed]

This is just a question for discussion. I've found that many users usually use SSH only as a tunneling protocol. It is very useful when you are going to mask your network traffic in SSH traffic to ...
-1
votes
0answers
18 views

How to install linux-headers-2.6.32-2

My system is running on linux kernel 2.6.32-2.I can't find linux-headers-2.6.32-2. So... can I download linux-headers-2.6.32-5-486? or I will get some incompatibility issues? I want to build module ...
0
votes
2answers
17 views

Posix map fs path to syspath

Is there a safe way to map a filesystem path to a /sys/block/ node. For instance on my system (Ubuntu) my / path is mounted from /dev/disk/by-uuid/7f6a93a7-1e63-48a3-a7e3-b336a2f9dbf7 which is a ...
0
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0answers
51 views

Kernel upgrade issue

I am trying to upgrade kernel on OnApp VM. Currently installed kernel is 2.6.32-279.22.1.el6.x86_64. The new version available is 2.6.32-504.16.2.el6.x86_64. I installed new kernel ...
1
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0answers
24 views

DRBD device temporarily disappearing across different kernel versions?

After upgrading from an old kernel to a new kernel version and booting into the new kernel the DRBD logical device was gone. Think nothing under /proc/drbd. This is a major problem as I have DRBD ...
2
votes
1answer
42 views

Can't execute any command

I can't execute any command on my Debian server, for exammple if I try to execute "reboot" command I have this : root@server002:~# reboot -bash: /sbin/reboot: Input/output erro Or if I want to ...
0
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0answers
197 views

Ubuntu 14.04.2 LTS - Errors on apt-get autoremove old kernel images - dpkg and grub errors

I was running my usual apt-get update / apt-get dist-upgrade sequence on my Ubuntu 14.04.2 LTS server, and saw some old kernel packages marked for autoremoval. I frequently run apt-get autoremove to ...
0
votes
1answer
13 views

Upgrading Web Application's Systems' Kernels for IW10 & other related improvements - upgrade all machines? LB first? Most important?

Stackers - We're making the push to upgrade the systems for our web app to take advantage of the various TCP improvements becoming more readily available (e.g. ...
0
votes
1answer
81 views

How to auto-start Degraded Software RAID1 under Debian 8.0.0 on boot?

If you remove a component HDD from an array, it drops into a "busy box" shell under "(initramfs)" saying something similar to "cannot mount root device" as the RAID1 array becomes "inactive". It is ...
-2
votes
1answer
49 views

I need to perform a kernel upgrade on a live system. Best practices? [closed]

Steps taken so far: apt-cache search linux-image* apt-get install linux-image-... I was now thinking of rebooting and selecting the new kernel when it appears on the GRUB menu, however: Is it ...
0
votes
1answer
45 views

VPS restarted for no reason. Why?

I have a VPS that runs a Java server, a redis server and a PostgreSQL server. Everything is running well but last night my server "crashed" at 3:15:50 AM. At least that's what I thought. I looked at ...
1
vote
3answers
81 views

Best way to disable swap in linux

I am running a custom compiled 3.18.9 kernel and I am wondering about the best way to disable swap on the system. I also use init if it makes a difference. Is it enough to comment or remove the swap ...
0
votes
0answers
10 views

convert SLES11 SP1 vmlinuz-3.0.13-0.27-xen to VMware using vmware converter

I am looking to convert a XEN VM (SLES11 SP1 kernel vmlinuz-3.0.13-0.27-xen) to a VMware guest using the VMware converter tool. The VMware tool tell me conversion went fine. 100% OK, however, when I ...
1
vote
0answers
9 views

Seeing what Linux kernel compile options where used [duplicate]

Is it possible to tell what compile options a running Linux kernel has been built with? I am particularly interested in those that impact on preemptive behavior, such as CONFIG_PREEMPT_VOLUNTARY. ...
1
vote
1answer
54 views

TSC missing from available clocksources

Not sure why TSC as a clock source is not available? cat /sys/devices/system/clocksource/clocksource0/available_clocksource hpet acpi_pm The CPU I'm using is Intel Xeon(R) X5570 @ 2.93GHz. The ...
0
votes
1answer
115 views

Kernel: dst cache overflow

I'm under continuous floods at time that are generally of lower magnitudes. I've observed my system often to become totally unresponsive on its network while I observed this in the logs, kernel: ...
1
vote
0answers
51 views

Kernel panic under DDOS

I'm running a Debian 6 - 64bit system (Kernel 2.6.32-5-amd64) and often get flooded with DDOS. I have tuned the network parameters under /etc/sysctl.conf to not let any kernel parameter overflow. ...
0
votes
0answers
33 views

switch_root not included in initramfs image

After upgrading the kernel via yum to the latest version the initramfs image file is missing the switch_root binary from the /sbin/ folder. This causes the machine to not boot, from this kernel. ...
0
votes
1answer
30 views

IO does not share in multiple CPU

In my linux server IO doesnot share in multiple CPU. as below output ata_piix intrupts share in only cpu0 [root@manage ~]# uname -a Linux manage 3.14.24-1smp #12 SMP Tue Mar 17 15:33:27 IST 2015 ...
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0answers
27 views

Why would kern.log stop logging after crash & reboot

Server: Ubuntu 12.04 I recently noticed that my servers kern.log had stopped logging. I've not separated iptables from the kern.log so it used to be very active, however recently it's been logging ...
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votes
1answer
41 views

Debian diffence between kernels [closed]

Debian Wheezy installer What's the difference between the first and the second kernel?
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0answers
50 views

detecting whether GPUs are accessible before running nvidia-smi during boot to create dev files

In the past, I've successfully configured Ubuntu systems containing NVIDIA GPUs to launch nvidia-smi in the background from within /etc/rc.local during the system boot to create the requisite ...
0
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0answers
18 views

Run compiled kernel with mcp251.x support

I have jetson tk1 board with ubuntu 14.04 pre-installed. I want to add mcp2515 functionality to it. How can I get it running? First of all, I set up the support of can bus in kernel and make and ...
0
votes
1answer
149 views

SSD caching using bcache or dm-cache on kernel 2.6.32-042stab104.1

I'm looking to use bcache or dm-cache with the latest OpenVZ kernel (2.6.32-042stab104.1) on CentOS 6. Unfortunately, dm-cache and bcache are part of kernel 3.10, but I know the OpenVZ kernel has a ...
0
votes
3answers
104 views

Kernel Processes Periodically Eating CPU During High Load

I run a production web server with 24 cores in which the work is both CPU and I/O intensive, but mostly CPU. My scripts delay execution when total CPU load is ~85% or higher in order to keep the load ...
0
votes
0answers
22 views

Broadcast ARP weirdness

we a running a router on a custom Linux box. Kernel is 3.14.14. What happens is that when you arping the router in broadcast only mode is the router has a verey slow response time: # arping -b -c ...
0
votes
1answer
95 views

Compiling an individual kernel module (Debian/Ubuntu)

I need to modify the ELF loader's kernel implementation of an Ubuntu 14.04 distribution. Having downloaded the sources using: sudo apt-get source linux-image-$(uname -r) I ran the configuration ...
1
vote
1answer
73 views

how to debug futex congestion in system

I have perl multithreaded script ("assp antispam proxy") that uses multiple perl libraries. On one of my servers after about 2 hours script starts to make huge number of futexed which consumes a lot ...
0
votes
2answers
210 views

grubby fatal error: unable to find a suitable template

I'm trying to fix my system after moving it from one server to another. It works perfectly with kernel booted via network, but not from the disk. Reinstalling stock CentOS 6.6 kernel shows this ...
0
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0answers
38 views

Network Interfaces Cards and rx_short_length_errors and Linux Kernel

My machine (Linux OS) is counting packets with wrong length, it is a huge environment (GW's, Routers, Switches...) , so I would like to understand how NIC's behaving with these packets. -Does NIC's ...
0
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2answers
65 views

Can a Linux Kernel be shared between two operating systems?

Quite simple question. I am working on a project to have multiple operating systems (all linux) on the same machine using btrfs subvolumes so that the user can boot to the environment they are ...
0
votes
0answers
106 views

Cannot start OpenVZ container

When I try to start container I got Starting container... Opening delta /var/lib/vz/private/100/root.hdd/root.hdd Adding delta dev=/dev/ploop15117 img=/var/lib/vz/private/100/root.hdd/root.hdd (rw) ...
2
votes
1answer
46 views

Use VPS provider's kernel or maintain my own?

I've got a Debian Wheezy VM on Linode and they run it with their own kernel. As a reputable company, I'm sure they're quick to apply security patches, and all I need to do is reboot to get the new ...
1
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0answers
87 views

Upgrading CentOS from 6 to 7 has broken my boot sequence

I ran the upgrade assistant provided by CentOS for upgrading from CentOS 6 to 7. The upgrade appeared to have been a success, however my system now hangs when trying to boot up. (Keep in mind I have ...
0
votes
1answer
93 views

New linux with old kernel in chroot [closed]

I have access to enterprise level server, but it have kernel version Description: Red Hat Enterprise Linux Server release 6.4 (Santiago) Release: 6.4 Codename: Santiago ...
0
votes
0answers
101 views

How to find what is causing a Kernel EventTracing error in the Event Log?

I am troubleshooting a Kernel EventTracing: "session failed to start with the following error: 0xc0000011" that pops up too many times in my event log. Every solutions I found in google were very ...
0
votes
1answer
47 views

Enable IP forwarding inside an OpenVZ container but disable it on host

Is it possible to enable IP forwarding inside an OpenVZ container but keep it disabled in host system? I understand that OpenVZ containers and host share kernels, but I can use sysctl to set ...
2
votes
0answers
93 views

BUG message on xenserver 6.5 - bad memory?

Several times a day I receive the following error in /var/log/messages. The server hangs and requires a reboot to respond again: Feb 1 13:44:54 xenserver-abfuqvrs kernel: [35023.166776] BUG: unable ...
0
votes
1answer
36 views

What does the tcp_fastretrans_alert error mean?

I found this error a couple of times in /var/log/messages after experiencing some odd TCP behavior: For some reason, if I connect to for example SSH for the first time in say an hour, the connection ...
0
votes
1answer
48 views

Which is the physical device behind the logical /dev/___ device

From time to time I get myself dealing with this same problem: from a linux logical block device (something below /dev/), I need to find the actual hardware behind it (something probably being listed ...
1
vote
0answers
43 views

make linux kernel read swap back into memory [closed]

Occasionally, I run a script that uses the majority of the 16GB of physical memory on my workstation. The kernel then swaps out the rest to swap partitions on multiple disks. After the script is ...
3
votes
2answers
1k views

VMWare ESXi error upon boot “Relocating modules and starting up the kernel”

Coming back from a 4-day weekend, I noticed the A/C had been turned off for the duration of the long weekend and the heat was around 80-82 degrees. The HP ProLiant DL185G5 was running but the system ...
1
vote
1answer
54 views

Influence of kernel code execution to Load average in top?

I'm trying to tests the amount of CPU that iptables use for NAT. Perhaps it will be more accurate to say "the amount of CPU that the netfilter kernel module" uses. The approach i took was to try and ...
3
votes
1answer
65 views

How to keep specific old kernels around after a yum update

I know that in CentOS 6.x, you can put the following line in /etc/yum.conf which tells yum to keep the last N kernels (by default this is set to five): installonly_limit=5 However, there are cases ...
15
votes
2answers
362 views

Does the “bs” option in “dd” really improve the speed?

Every now and then, I'm told that to increase the speed of a "dd" I should carefully choose a proper "block size". Even here, on ServerFault, someone else wrote that "...the optimum block size is ...
1
vote
1answer
32 views

Kernel dependency error on Ubuntu 12 server

I was doing my quarterly updates of an Ubuntu 12 server. After an apt-get update succeeded I'm getting this error running apt-get anything. Depends: linux-image-server (= 3.2.0.72.86) but it is not ...
0
votes
0answers
32 views

How does a kernel patch propagate into distribution updates?

I have been affected by, and helped to debug, a kernel bug. A patch has been created by the maintainer of the module, and submitted. I am interested to know how the patch propagates through to binary ...
4
votes
3answers
185 views

Modifying kernel cmdline in Ubuntu

I have a number of systems on which I need to modify the kernel cmdline, adding a few options. At the moment I do it using the following procedure: Open /etc/default/grub Modify ...
2
votes
0answers
903 views

OpenVPN ERROR: could not insert 'tun': Unknown symbol in module, or unknown parameter (see dmesg)

I'm trying to configure OpenVPN on my Debian 7 VPN but I'm getting the following error ERROR: could not insert 'tun': Unknown symbol in module, or unknown parameter (see dmesg) I tried the ...