I upgraded a box from CentOS 4.2 to 4.3 this evening. You might think “no problem there” – rebooted it and it didn’t come up.

The following error was on the terminal after the reboot

“LOADING PBR FOR DESCRIPTOR 1. DONE

BAD PBR SIGNATURE.”

Basically this means the mbr is shagged on your disk.

A quick boot off of a centOS cd “linux rescue”, mount you system and chroot into it.

Type:

$ grub
$ grub> root (hd0,0)
$ grub> setup (hd0)
$ grub> exit

That is it, grub will have re-installed itself and the machine will boot. The server in particular was a brand new, Dell Poweredge SC1425, 2 x 3.2Ghz Xeon processors etc.

We live and learn.

I found syslog-ng last week. I’ve since rolled it out on the new network. The core routers and distrution routers log to this now. It’s pretty handy and makes searching for oddities or problems much easier.

You can search per IP, per service or have it exclude certain txt terms. I’ve found it extremely flexible so far. The beauty of it is I can also have the boxes log to disk elsewhere aswell.