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 ...

learn more… | top users | synonyms

0
votes
0answers
4 views

Debian Jessie 8 idle on fresh install always a little too high, shows rcu_sched ksoftirqd kworker causing cpu load

Are the days of 0.0 cpu load on an "idle" server gone? I have another server (centos/redhat) 32GB ram that actually runs apache/MySQL/Lamp, mono, redmine/ruby, and other junk and its still shows me ...
0
votes
0answers
11 views

/proc/stat btime value change after boot

In a Linux server with the kernel 3.16, not virtualized, but with the ntp daemon active, the variable "btime" wich gives the time at which the system booted, change a few seconds before booting. For ...
1
vote
1answer
19 views

cpufrequency scaling with debian 8.1 and Intel XEON E5-1650 v3

I want my server with debian 8.1 not to use cpu scaling but always run at the highest possible frequency. I have installed cpufrequtils $ dpkg -l | grep cpufreq ii cpufrequtils ...
0
votes
0answers
5 views

CONFIG_NF_CONNTRACK is not set [migrated]

I am trying to setup iptables on udoo quad but I hit a brick wall and cannot find a fix anywhere: root@udoo:/# uname -a Linux udoo 3.0.35 #10 SMP PREEMPT Wed Jul 30 18:16:10 CEST 2014 armv7l ...
0
votes
1answer
33 views

Rebooting a production CentOS 6 server that's been up for 365 days

I noticed today when running uptime that my server has been up for exactly 365 days. Which led me to google "should I periodically reboot my server". Which led me to the knowledge that YES, I should ...
0
votes
0answers
83 views

task nginx:4164 blocked for more than 120 seconds

My server was working fine for 173 days then it started to happen. Upgrading CentOS 6.6 kernel to latest one didn't helped. Rebooting helps for about 10 minutes then it starts all over again. I'm ...
0
votes
1answer
44 views

centos doesn't reply to icmp request

I have the following situation: Centos7, 2 NIC with following setup: em2(NIC2) : 82.79.24.74/29 82.79.24.75/29 em3(NIC3) : 192.168.0.240/24 192.168.133.240/24 ...
-1
votes
1answer
19 views

AWS Instance Kernal-id

I am running a Windows Server instance in AWS Cloud.I have created a snapshot for the same. When i'm trying to create a AMI from my snapshot it is asking Kernel-ID and RAM Disk ID. I don't know what ...
2
votes
1answer
55 views

CentOS, kernel: out of memory

Hope you can help me with the following problem. We are running a CrushFTP service on a CentOS release 6.6 (Final) system. But nearly every week the service crashes. So I take a look at the logs and ...
1
vote
0answers
27 views

slabtop command doesn't work

I've inherited Sys Admin duties on webserver and I'm a bit of out my element, but learning as I go. My newest issue is all the of the ram has been gobbled up and I'm not sure where it has gone. free ...
0
votes
0answers
19 views

How to hot add a new disk with virsh attach-disk?

I'm trying to add a new LVM disk to my guest machine (Ubuntu 14.04.1) by doing the following on the host: lvcreate -L 14G -n vm_vm005_data3 vg00 virsh attach-disk vm005 /dev/vg00/vm_vm005_data3 ...
0
votes
1answer
46 views

snmpd does not update date due to filesystem access error in new ubuntu versions

My Cacti stopped graphing network data for servers that I monitor using snmp. I am able to manually query the corresponding counter using snmpget $ snmpget -v 2c -c XXX XXX .1.3.6.1.2.1.31.1.1.1.6.4 ...
0
votes
0answers
14 views

disabling ip_forward for ubuntu server

This is the state of my server right after booting: root@vzu01-ubuntu:~# uname -a Linux vzu01-ubuntu 3.16.0-30-generic #40~14.04.1-Ubuntu SMP Thu Jan 15 17:43:14 UTC 2015 x86_64 x86_64 x86_64 ...
1
vote
2answers
56 views

Wchan section in ps output not showing anything

I know that if a process go into D state then it means that it is in uninterruptable state. The process can not be killed by any signal. It will only come out of that state on reboot or if I/O wait is ...
0
votes
0answers
30 views

Diskless node. Unable to mount root fs via NFS

Server: CentOS 7 NFS root filesystem for client and Kernel: Slackware 14.1 I enabled "Root file system on NFS" and "IP: kernel level autoconfiguration" with "DHCP,BOOTP,RARP" support, recompiled the ...
0
votes
1answer
149 views

Building CentOS 6 kernel with KVM support fails due to MMU

When building the latest Linux kernel for CentOS it turns up the following error CC [M] arch/x86/kernel/iosf_mbi.o CC arch/x86/kvm/../../../virt/kvm/kvm_main.o CC ...
0
votes
0answers
68 views

Add nmi=ignore to default xen boot option

I updated my Xenserver from 6.2 to 6.5 and the server won't boot unless I deactivate Hyper Threading via BIOS (INtel Server Board). I can fix that using a special kernel parameter (nmi=ignore) but I ...
0
votes
1answer
166 views

Debian 8 Jessie with older Kernel - Do I have to expect problems?

I have a virtual server that I tried to upgrade from Debian 7 to Debian 8. Unfortunately, I cannot use the new kernel: it still uses version 3.2.41-042stab108.2. Everything else seems to have been ...
0
votes
1answer
83 views

How can I modify kernel command line in CoreOS

I am trying to set 'net.ifnames=0' on the kernel command line for CoreOS. In older loads (including the current stable 647.0.0), you could mount /dev/sda1 and edit the grub.cfg file under ...
0
votes
1answer
88 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 ...
0
votes
2answers
20 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
votes
0answers
87 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
vote
0answers
26 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
53 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
votes
0answers
390 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
26 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
432 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
51 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
65 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
180 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
1answer
28 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
87 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
320 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
57 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
45 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
33 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 ...
0
votes
0answers
51 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 ...
-2
votes
1answer
47 views

Debian diffence between kernels [closed]

Debian Wheezy installer What's the difference between the first and the second kernel?
1
vote
0answers
100 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
votes
0answers
20 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
246 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
223 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
29 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
232 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
140 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 ...
1
vote
2answers
432 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
votes
0answers
74 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
votes
2answers
71 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
149 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) ...