FirstServed Tech Blog - FirstServed and the Art of Server Tuning

Hi,

If you want to configure a serial console on your Dell PowerEdge R410 (or R710) dedicated server with CentOS 5.4 (or 5.3 and probably also the Red Hat Enterprise systems) you can use these guidelines.
In the Bios:

Under "Serial Communication":
Serial Communication: On with Console Redirection via COM1
Serial Port Address: Serial Device1=COM2,Serial Device2=COM1
External Serial Connector: Serial Device2
Failsafe Baud Rate: 115200
Remote Terminal Type: VT100/VT220
Redirection After Boot: Enabled (so grub displays)

Then you configure Grub:

title CentOS (2.6.18-164.6.1.el5) Serial
root (hd0,0)
kernel /vmlinuz-2.6.18-164.6.1.el5 ro root=LABEL=/ console=tty0 console=ttyS0,115200n8
initrd /initrd-2.6.18-164.6.1.el5.img

This makes the kernel display it’s messages on screen and over the serial console.

In /etc/securetty append:

ttyS0
ttyS1

This way root can log in using the serial console.

Finally configure the inittab (/etc/inittab) and add the following line:

co:2345:respawn:/sbin/agetty ttyS0 115200 linux

Now reboot and enjoy pure serial console goodness over ip (ipmi).

(Oh, don’t forget to enable IPMI over lan in the iDrac configuration and to set a username, password and ip-address.
The iDrac 6 configuration flashes by when the server boots.)

When connecting to a Juniper router’s console port, do not use your everyday DB9-DB9 serial cable!
Although the Juniper M7 qualifies as a computer which runs BSD, it won’t be able to communicate using this type of cable.

So, what cable should you use?
Use a standard Cisco Roll-over cable, and use an RJ45 – DB9 converter at the router’s side (or both sides, depending on wether the cable had a build in DB9 connection at one of it’s sides).

Use this command to read the BIOS dmi data in linux:
dmidecode

Reads mainboard type, bios version, memory banks, …