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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2
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1answer
95 views

High shmmax value in Redhat 6.3

We are using Redhat 6.3 with 30G RAM to host our Postgres server. The (default) shmmax value is 68,719,476,736 In some forums I have read that having an shmmax value larger than the RAM causes ...
0
votes
1answer
100 views

Multiple ethernet interface on one ethernet card

First I must say that I am new in linux and maybe I will ask trivial question. My job is to create 8 ethernet interface to be visible in kernel, but all of them should send and receive data through ...
1
vote
0answers
308 views

Xen hangs on boot when scrubbing RAM

I have a CentOS 5 server I can boot into the stock kernel just fine, but when I try kernel-xen, it gets stuck here: http://i.stack.imgur.com/wAI20.png When I try adding no-bootscrub to the kernel ...
0
votes
1answer
770 views

How can I diagnose and fix frequent 100% cpu utilization from kernel?

I have an Amazon EC2 micro instance running an old 2.6.16 kernel. It runs postfix, apache, and mysql. During normal loads, it's load average is around 0.05, and it runs this way 95% of the time or so. ...
1
vote
1answer
871 views

RHEL 6.0 upgrading kernel from 2.6.32-71.el6.x86_64 to 2.6.32-358.2.1.el6.x86_64

[root@localhost ~]# rpm -ivh kernel-2.6.32-358.2.1.el6.x86_64.rpm error: Failed dependencies: bfa-firmware < 3.0.3.1 conflicts with kernel-2.6.32-358.2.1.el6.x86_64 [root@localhost ~]# rpm ...
3
votes
2answers
340 views

“Never take kernel updates” — Any truth to this?

So I am having a discussion with a coworker today, and he let something out that I thought was bizarre, as I'm getting ready to apply security updates to one of our production servers. "You should ...
2
votes
2answers
2k views

Kernel 3.8, Apache2 with WSGI : INFO: task apache2 blocked for more than 120 seconds

We have upgraded our Kernel from 2.6.32 to 3.8.7 on a Debian system. We have a sharing with NFS to get the data for Apache2. And Nginx serves only static files as a proxy. Since we have installed the ...
0
votes
2answers
186 views

Check my Kernel for SELinux Support

I want to know if the kernel i am running has support for SELinux. What commands would i use to check this ?
1
vote
1answer
558 views

Adaptec RAID array was not detected after updating the kernel?

Continue from this topic, the newer kernel booted successfully but it doesn't see my sdc - which is a hardware RAID array (level 10). I'm sure the aacraid module is loaded: # grep aacraid ...
2
votes
1answer
831 views

Kernel attempts to kill MySQL with sigkill

I'm running an Ubuntu server for MySQL. Server info Ubuntu 12.10 MySQL installed via apt RAM: 512M innodb_buffer_pool_size : 300M There is no other memory intensive application running on this ...
1
vote
2answers
348 views

Kernel Configuration, Which Processor family?

Which processor family should I use for the cpu shown below for the best fit?
1
vote
2answers
50 views

Debian Squeeze Kernel

I'm running Debian Squeeze completely up to date on a machine. However when running uname I see that I'm on a very old kernel: $ uname -r 2.6.32-5-amd64 Is this normal for Debian Squeeze? Should I ...
1
vote
2answers
375 views

Increase FD limitation then SSH not working?

I'm using CentOS 6.3 64bit, and having trouble with increase FD limitation: SSH not working after changed the limitation, every-times I logged on my server, after typed password, then "connection ...
1
vote
0answers
310 views

CentOS 6 won't load default (new) kernel, loads (another) older one instead

I am having a weird issue with a CentOS 6 system. I have upgraded the kernel twice now and when I reboot the system it still loads the older kernel. I also had a dc tech watch the screen as it ...
1
vote
1answer
138 views

Apache2 reload and System Crash

Reloading Apache2 caused Ubuntu 11.04 to Hang/Crash. Load average was 32 CPU Cores:8 Model: Intel xeon E5620 RAM:16 GB Kernel :2.6.38-13-generic Apr 6 09:05:11 406852 kernel: [3715446.033031] ...
0
votes
1answer
251 views

Is tcp_keepalive application dependant on Linux?

According to http://tldp.org/HOWTO/TCP-Keepalive-HOWTO/index.html , the kernel keepalive function occurs at the OS level, and doesn't require an application to explicitly call it. However I also read ...
4
votes
3answers
756 views

Compiling kernel version >= 2.6.34 on CentOS 5: RAID set “ddf1_foo” was not activated?

I want to mount a Ceph FS on some CentOS 5 servers. Since the ceph-fuse failed with below errors: # ceph-fuse --no-fuse-big-writes -m 192.168.2.15:6789 /mnt/ceph/ ceph-fuse[7528]: starting ceph ...
0
votes
2answers
888 views

Issue on yum update with kernel

--> Running transaction check ---> Package e2fsprogs-resize2fs-static.x86_64 0:1.42.3-3.el6.1.ovz will be installed ---> Package kernel.x86_64 0:2.6.32-358.2.1.el6 will be installed --> ...
3
votes
3answers
6k views

CentOS 6: strange page allocation failure messages [duplicate]

I set up a new Server with CentOS 6.4 final as successor for an old mysql server and I'm facing some problems with it. From time to time mysql connections are being disconnected. Furthermore the ...
0
votes
1answer
67 views

Compile Kernel Debian Squeeze

Am newbie, and I'm trying on Debian Squeeze to upgrade/compile kernel for problem I'm having with Linux-Vserver. The instructions I'm trying to use start with "apt-get installlinux-source-2.6.32" and ...
1
vote
2answers
1k views

Linux server resend SYN ACK

I am troubleshooting a connection timeout problem between two Linux boxes, where it seems the ACK to SYN-ACK was lost on the server's stack. The tcpdump is done on the server side. The client got ...
0
votes
2answers
2k views

CentOS 6 Xen guest fails to boot after 'yum update'. Kernel?

I Seem to be having an issue with a Xen guest not booting after a yum update. DomU Configuration: #kernel = '/boot/solus-vmlinuz' #ramdisk = '/boot/solus-initrd.img' bootloader = ...
3
votes
1answer
197 views

firewall output flooding dmesg

I log all dropped packets using following iptables rule: -A INPUT -j LOG --log-prefix "FW_DROP: " --log-level 7 and then in rsyslog.conf, I redirect this output to a separate file, so that my ...
0
votes
1answer
250 views

Effects of IW10 (initcwnd 10 initrwnd 10) on high speed LAN based TCP/IP communications?

What does changing the number of packets sent during the initial congestion window to 10 have on LAN connections? Via: ip route change default via GATEWAY dev INTERFACE initcwnd 10 initrwnd 10 Is ...
1
vote
0answers
301 views

UDP socket receive buffer size change on RHEL6.3

Our system used to work on RHEL5.3 And the socket receive buffer size is 64k. And that works fine. We can get message size up to 64k on UDP socket. But after system upgrade, it is running on RHEL6.3 ...
0
votes
2answers
627 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 ...
9
votes
4answers
4k views

How can I troubleshoot high Kernel time?

I have unusually high Kernel time on my CPUs as shown in task manager. What are some ways I can troubleshoot this?
0
votes
1answer
458 views

mpt2sas1: log_info(0x31120303): Disks dropped from RAID

In my syslog I get loads of: Mar 1 11:20:07 franklin kernel: [72947.878407] Waking error handler thread Mar 1 11:20:07 franklin kernel: [72947.878415] Error handler scsi_eh_1 waking up Mar 1 ...
0
votes
2answers
348 views

Is the latest kernel mainline release stable [closed]

Looking at kernel.org the latest mainline release is 3.8. Zhe site also states the latest stable release is 3.7.9. Now looking at http://en.wikipedia.org/wiki/Linux_kernel inside the version history ...
-1
votes
1answer
193 views

btrfs balance kernel bug? [closed]

After getting a little annoyed with no space left errors when deleting files I started a btrfs balance process and 2-3 times the following appeared. Is this serious for my data or can I just ignore it ...
2
votes
3answers
471 views

How to install packages with APT without user interaction?

I have a script that downloads and replaces kernel headers in Debian squeeze. function fixHeaders(){ #Replace the kernel headers from OVH with standard kernel headers... aptitude -y install ...
2
votes
1answer
2k views

Kernel Errors Present: EXT4-fs

Logwatch is giving me the following error: WARNING: Kernel Errors Present EXT4-fs (sda1): error count: 4 ...: 1 Time(s) EXT4-fs (sda1): initial error at 1350482172: e ...: 1 Time(s) EXT4-fs ...
7
votes
2answers
614 views

/dev/shm & /proc hardening

I've seen mention of securing /dev/shm and /proc and I was wondering how you do that and what it consists of doing? I assume this involves /etc/sysctl.conf editing of some kind right. Like these? ...
4
votes
3answers
96 views

How to determine if a Debian upgrade updated the kernel

Let's say I have just done an aptitude safe-upgrade on a Debian system, but I was not paying attention so I did not notice if the kernel was updated or not. How can I now determine if there was a ...
2
votes
2answers
2k views

How to differentiate intentional reboot and power failure from logs

One of my centos host rebooted recently unfortunately no monitoring was implemented . How can i find out what caused it to reboot. i only have ssh access to it. How can determine if the cause is due ...
-1
votes
2answers
950 views

Why does Centos 6 have an older kernel than Ubuntu 12.04 [closed]

Hi can some one help me in understanding this. On Centos 6.2 its showing kernel as 2.6.32-220.el6.x86_64 whereas on Ubuntu 12.04 its showing as 3.2.0-23-generic. 3.0 kernel is one of the latest ...
2
votes
2answers
983 views

Xserve 10.6.8: Why do `net.inet.ip.forwarding` & `net.inet.ip.fw.enable` kernel sysctl settings stay enabled even disabling?

Very bizarre situation. I have inherited a few Xservers from a previous admin that I have been charged with cleaning up on various levels. I am familiar with settings in Ubuntu & am very ...
1
vote
2answers
190 views

Different uname -a results

I am working on a multi-server system for a client. All of the servers are fresh installs (although two were installed a couple of months ago, five a couple of days ago). They are all supposed to be ...
0
votes
1answer
639 views

How to check a driver version in linux kernel update

How I can find an information about the driver version in linux kernel update for NIC: Current: # uname -r 2.6.32-279.2.1.el6.x86_64 - # ethtool -i eth0 driver: e1000e version: 1.9.5-k ...
-1
votes
1answer
267 views

Network kernel issue dst overflow

I am currently having a issue with my server, apperently after awhile, my network will slowdown and later stop working. It shows this: Dst overflow My kernel is 2.6.18-308.8.2.el5.028stab101.1 #1 ...
0
votes
1answer
125 views

Add generic rescue kernel on Gentoo

I have a Gentoo machine (64-bit) with software RAID on boot which was set up previously by someone who optimised the kernel for that machine. Now I want to shift the disks to a new machine (also ...
1
vote
0answers
640 views

“sched: RT throttling activated” KVM host - what does this mean?

Ubuntu 12.04 64bit - under a KVM parent. 32 cores. So we seem to be having some load issues. We have noticed this line in kern.log: "kernel: sched: RT throttling activated" What does this mean? Is the ...
0
votes
2answers
214 views

Solaris 11 nsswitch.conf messed up, need to edit it from an alternate kernel

Ok, so I was editing the name-service/switch service and messed up my nsswitch.conf, I overwrote the "passwd = files" with "passwd = filesasdf" so now I can't auth to the server when I boot that ...
0
votes
1answer
104 views

Cloning instance - Original kernel not available when creating AMI

I have a EC2 Ubuntu server on Amazon cloud and I'm trying to clone an instance "X" by creating a snapshot of the instance and creating an AMI from that snapshot. The problem is: When creating the AMI, ...
0
votes
1answer
97 views

Kernel panic - not syncing: BRKADRINT

One of the machines on the network started beeping continuously and was unresponsive locally as well over the network. We shut it down keeping power pressed. Upon reboot, the boot stopped with Kernel ...
2
votes
2answers
112 views

What is the latest valid release of kernel 2.4

I want to download the latest valid release of kernel 2.4. I look at ftp.kernel.org and here the highest release available is 2.4.31, while searching on others mirrors I found that ther is also ...
1
vote
1answer
87 views

saving loaded kernel modules

I did the following in command line: modprobe ipt_LOG modprobe ipt_multiport modprobe ipt_state modprobe ipt_limit modprobe ipt_recent modprobe ipt_owner modprobe iptable_nat modprobe tun/tap ...
0
votes
0answers
51 views

enabling modules for a kernel

I have a KVM/XEN VPS and would like to enable the following modules: ipt_LOG ipt_multiport ipt_state ipt_limit ipt_recent ipt_owner iptable_nat tun/tap iptable_nat ipt_MASQUERADE ipt_POSTROUTING PPTP ...
1
vote
3answers
183 views

Performance impact of running kdump

We are currently running into an issue on a RHEL 5.6 server. The server randomly becomes unstable, kernel wait messages are showing up in /var/log/messages, and we've now had it reboot twice. We've ...
-2
votes
1answer
342 views

linux + from where uname -r take the linux version information

when I type the uname -r command on linux: uname -r I get the following info: 2.6.18-274.7.1.el5PAE my question from which file uname -r read this info , or from where uname -r read the Data ? ...