In this post I will present a little story of what happened to me today. As I was working to upgrade the kernel on one server (remote of course), something very funny (at least if I look at it now) happened. When upgrading a kernel on a remote server there is always a chance (even if you are very experienced and done this several times, still there is a small chance) that something will not work as expected and when rebooting the system to no have it back online. Even though I have a good experience on doing this and I can’t remember since I have ‘lost’ a system when upgrading its kernel, I am always very careful when doing this.

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If you want to look what is inside of an initrd file (don’t ask me why I needed this ;)), here you can find some information on how you can do that. Depending on what kernel you are using you might encounter various initrd type of files. Read the rest of this entry »

Most recent linux distributions (CentOS 4, Fedora 3+, RHE 4, etc) are NPTL (Native POSIX Thread Library) based. If you want to check if your system is NPTL based, or only if you want to find out what version it is present in your kernel, you can use the following command:

getconf GNU_LIBPTHREAD_VERSION

Sample results:
On a Debian Etch system:

getconf GNU_LIBPTHREAD_VERSION
NPTL 2.3.6

On a RHEL4 system:

getconf GNU_LIBPTHREAD_VERSION
NPTL 2.3.4

For a detailed description on NPTL you can check wikipedia.