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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About kernel upgrade

If I upgrade the kernel,will old binaries use new version of .so or still the old version? UPDATE Why kernel has nothing to do with .so?
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Very low performance of raid6

I noticed that writing to raid-6 is very low, but when I make tests with hdparm the speed is reasonable: dd if=/dev/zero of=/store/01/test.tmp bs=1M count=10000 Gives: 50Mb/s or even less. The ...
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how to enable ipv6 in redhat

can anyone tell me how to enable ipv6 support in rhel i tried sysctl -w net.ipv6.conf.all.forwarding=1 and echo 1 > /proc/sys/net/ipv6/conf/all/forwarding and did service network restart but still i ...
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How to compile the kernel with debug symbols? [closed]

I've already finishing compiling the kernel from source, but how to compile it with debug symbols,what additional steps to I need to take?
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What can be the reason for “Invalid module format”?

I'm following the steps to compile kernel 2.6.32 from source, and have no problem to go the the last step: ... make modules_install make install And I've also configured grub.conf correctly. But ...
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How can I see logs in a server after a kernel panic hang?

I am running a production gentoo Linux machine, and recently there was a situation where the server hung in my co-located premises and when I got there I noticed that the server was hung on what ...
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1answer
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Linux buffer cache effect on IO writes?

I'm copying large files (3 x 30G) between 2 filesystems on a Linux server (kernel 2.6.37, 16 cores, 32G RAM) and I'm getting poor performance. I suspect that the usage of the buffer cache is killing ...
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1answer
94 views

Is upgrading your kernel analogous to patching in Windows?

Coming from mostly a Windows background, it seems to me that updating your kernel in Linux is essentially the same idea as patching the OS in Windows. Is this the case? What are the commonalities and ...
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2answers
334 views

linux kernel buffer memory is zero

There are one qestion that i can`t find in google. I have many linux boxes mostly with SLES or openSUSE, diffrent versions and kernels. On some of them i faced with slow oracle transactions problem. ...
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607 views

Meaning of tcp_delack_min

the current Linux Kernel (e.g. 2.6.36) uses Delayed Acknowledgments (delack). In /include/net/tcp.h it says: define TCP_DELACK_MIN ((unsigned)(HZ/25)) So, for a Kernel using a HZ value of ...
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enabling ipv4 forwarding locked up machine. ideas?

Hey. I'm running cent 5.5 64-bit, 1 nic, eth0. I enabled ipv4 forwarding via: echo '1' > /proc/sys/net/ipv4/ip_forward and the machine locks up. cant switch ttys cant ssh into it. Had to hard ...
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1answer
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Our embedded linux system won't recognize a USB Device if it is plugged in before powerup. Suggestions?

We are developing on a small embedded device. This device us a gumstix overo board running OpenEmbedded linux. We have our development almost completely done, and have run into the strangest of bugs ...
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1answer
613 views

exploit.so dmesg errors

A server (which has since been pulled offline and is scheduled to be wiped) was compromised through ssh brute force. No root/su/sudo access was gained but I started observing these errors (pasted ...
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1answer
971 views

Ubuntu 8.04 LTS Hardy: Upgrade kernel to 2.6.32?

I am facing an incompatibility issue between Ubuntu 8.04 LTS (Hardy) and the PERC 6/i RAID controller on our Dell PowerEdge R710 servers. Various forum posts (Ubuntu forum) confirm that other users ...
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0answers
583 views

How to modify Ubuntu 10.04.1 Grub entry for supporting KGDB kernel image

I am trying to update target m/c grub.cfg file for KGDB setup but while booting the m/c it got hung completely and not asking/waiting for remote gdb connection. Following is the entry which I added:- ...
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2answers
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Building and installing a kernel that can mount / from an EXT3 on an LVM2 device

I have an ageing but much loved Fedora Core 6 box for which I am attempting to compile a kernel more recent than 2.6.22, in order that I might employ its support for an eSATA card. My Fedora box has ...
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1answer
226 views

Possible to write an implement of RAIDZ or RAIDZ2 for the MD driver in the Linux kernel?

I am curious on if it is possible to have an implement of RAIDZ and/or RAIDZ2 in the MD driver in the Linux kernel? From my understanding of it is that the RAIDZ version is equivalent to a RAID 5, ...
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How can i break my own linux kernel [closed]

I was reading the linux book which says this Finally, if you break your kernel or boot loader, you won't be able to get to single-user mode without extra help. You can often boot your system ...
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Kernel panic almost daily, why?

Running latest version of CentOS 5 64. Get these almost daily, at totally random times. The box is a file delivery machine, that usually sends around 2.3Gbit Message from syslogd@localhost at Jun 28 ...
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Will modules installed by insmod command persist after rebooting?

There is how the book I'm reading describe the insmod utility: The program loads the module code and data into the kernel, which, in turn, performs a function similar to that of ld, in that ...
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4answers
319 views

Where is the Linux source kept in a Rackspace Gentoo VPS?

I'm emerging udev and it complains it couldn't find the kernel sources under /usr/src/linux (there's nothing inside /usr/src/ indeed). As a result, it tries to take the version from the currently ...
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Storage drives is causting system crash

I'm running Centos 5.4 with 750GB(ntfs) and 2TB drives for storage. Originally I installed the 750, everything seemed fine and then I installed the 2TB drive with NTFS already partitioned. I noticed ...
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best practice after upgrading the kernel

Greetings ... I need to know what anyone should do after upgrading the kernel ? How to do quick check if the kernel is suited for the server's softwares , check whether if kernel is compilable with ...
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2answers
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Linux memory fragmentation

Is there a way to detect memory fragmentation on linux ? This is because on some long running servers I have noticed performance degradation and only after I restart process I see better performance. ...
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154 views

Changing MAC address on the Fly on old kernel 2.6.x

I'm doing some research on old kernels and running the following on 2.6.7 or 2.6.8 gives a resource busy error. But on 2.6.28 the command works as expected. How would I determine which kernel allowed ...
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9answers
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Maximum number of files in one ext3 directory while still getting acceptable performance?

I have an application writing to an ext3 directory which over time has grown to roughly three million files. Needless to say, reading the file listing of this directory is unbearably slow. I don't ...
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3answers
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Munin “Available entropy” when using address space layout randomization

Having just configured Munin for statistics logging on my gentoo server (hardened profile), I am noticing that my "Available entropy" is consitently in the 200-300 range. This seems way to low, so I ...
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1answer
892 views

traffic shaping with “netem delay” works ok, but limits upload bandwidth to 330KB/s. Why?

I'm using Ubuntu 9.04 and the kernel 2.6 build-in NETEM tool to delay traffic. After I apply: tc qdisc add dev eth0 root netem delay 100ms The upload bandwidth can't go further than 330KB/s and I ...
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2answers
337 views

Please explain the following o/p of “top” command

Please explain the following line from the "top" command in the bold :- Mem: 1026228k total, 449640k used, 576588k free, 44812k buffers Swap: 1052248k total, 2020k used, 1050228k ...
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4answers
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How can Linux run on different microprocessors?

How can Linux run on different microprocessors? Is the Linux kernel being compiled at installation each time?