Arrfab's blog Some tips and tricks, mostly around CentOS

Thanks to X-tend , CentOS will be present at the Linux World Expo in Belgium this year. We (Dag Wieers and myself) will distribute flyers and try to show CentOS 5 in action. This was not really scheduled, but it's always a good idea to show CentOS to people who never heard of it ... especially when you know that, unlike the Fosdem that is attracting more geeks, the Linux World Expo tends to attract Enterprise Linux users (by inviting commercial companies like Redhat, Novell, and companies offering support for linux in belgium ). We hope to see people already using upstream distribution to at least be aware that CentOS exists ... Pictures and comments will come after the event ...

I had the chance this year to participate with the CentOS team ... too much people at 'le roy d'espagne' cafe for the beer event so we had to move and go to another bar ... some pictures are available on my website and my presentation is available (with other centos fosdem team members presentations) on the CentOS wiki

Each time i want  to use framebuffer in console i have to search kernel doc about vesafb about possible vga= entries.

Here they are :

{.alt2 style="border: 1px inset ; margin: 0px; padding: 6px; overflow: auto; width: 640px; height: 114px"} | 640x480 800x600 1024x768 1280x1024 ----+------------------------------------- 256 | 0x301 0x303 0x305 0x307 32k | 0x310 0x313 0x316 0x319 64k | 0x311 0x314 0x317 0x31A 16M | 0x312 0x315 0x318 0x31B

You can use it like that or convert hex in decimal : 0x317 then becomes 791

I don't like to play with software raid usually (i prefer real hardware raid card on servers ..) but i had to setup a small machine with 2 sata disks in raid 1. The problem is that after the reboot grub will fail to load the kernel (grub error 15).

Solution is to boot in rescue mode , issue a chroot /mnt/sysimage and setup grub manually on each drives :

grub

grub>root (hd0,0)
grub>setup (hd0)
grub>root (hd1,0)
grub>setup (hd1)
grub>quit

Reboot the machine and you'll have grub on each raid device ...

I had recently to setup CentOS 4.4 on a Acer desktop machine. Problem was that this machine (acert T180) contains a nvidia nforce chipset that neither centos default kernel or nvidia nforce driver disk (http://www.nvidia.com/object/linux_nforce_1.21.html) support ... Solution was to pass the 'all-generic-ide' parameter to the kernel ... it treats sata discs as ide but it works ... and performances seem roughtly the same ... tip : don't forget to give this parameter in grub.conf also so that your machine will reboot after the setup part ....

I have to do a presentation for the next fosdem (24-25 february 07) about using the belgian eID card under CentOS Linux. I'm busy with Dag Wieers to build the (provided by the belgian gov) sources as rpm packages but we need to patch it because some sources contains hard-coded values (shame on them ...) . I'll post when everything will be ready and hosted at rpmforge

echo '16i[q]sa[ln0=aln100%Pln100/snlbx]sbA0D4D465452snlbxq' | dc

This command will do the job for you for 99% of your problems ...

If you use ACLs on CentOS and want to keep your data synchronized with rsync, you probably already know that the standard supplied rsync doesn't support acls ... you then should use getfacl and setfacl on the target machine to replicate your acls .. but great news : a rsync rpm with acl support is in testing phase on http://dev.centos.org/centos/4/testing/i386/

I had recently to setup vmware server on a Fedora Core 6 but i encountered some problems during the vmware-config.pl post-setup step : it complained about linux.h ... Workaround was to `touch /usr/src/kernels/`uname -r`/include/linux/linux.h`

vmware-config.pl was happy after that file was created. This file was removed from the kernel tree for newer kernels and vmware-config.pl was searching this file ...

Why do i need to use M\$ windows and media player to watch some eu movies ? sign the petition too : http://www.petitionspot.com/petitions/eu_streaming_service_for_everybody