Setting Up Serial Debugging on Dell 11G Blade Systems in the M1000e Chassis
Windows debugging setup is relatively simple – you hook up the debugger system to the target via serial cable. However, Dell PowerEdge 11G Blade systems and M1000 chassis require some additional setup to establish the serial connection. Hardware setup for Windows or Linux debugging requires changes to the following:
- System BIOS
- Dell iDRAC (Integrated Dell Remote Access Card)
- M1000e CMC (Chassis Management Controller)
Follow the steps below to enable serial debugging on your M1000e chassis. We also have a similar article on enabling serial port debugging on Dell 12th Generation Servers.
System BIOS Configuration –
In POST (Power On Self Test), press F2 to enter BIOS
Next, select "Serial Communication"
Select Serial Communication
In "Serial Communication", set the following:
- Serial Communication - On Without Console Redirection
- Serial Port Address – Com1
- edirection After Boot – can be set to either disabled or enabled
This completes the BIOS setup portion.
Next, the iDRAC must be properly configured.
iDRAC Configuration –
During POST, you will see the following prompt as noted below:
"Press <Ctrl-E> for Remote Access Setup within 5 sec…."
Press Ctrl-E at that time.
Remote Access Setup
Once in the iDRAC configuration screen, disable IPMI Over LAN.
iDRAC Configuration Screen
This completes the iDRAC configuration changes.
Finally, you must set up the link between the CMC serial connector on the back of the M1000e chassis, and the specific blade you want to debug.
The serial connector located on the CMC is shown directly below – the other module is the iKVM module that does not have a serial connector.
Important note! In some configurations, you may have redundant CMCs – in this instance, you need to choose the primary (running) CMC controller to connect to – consult your documentation for more information. This becomes an issue because you must reset the CMC to clear the serial connection we will establish. This will trigger a switch to the backup CMC, so be aware that this will occur.
Important note 2! You must connect to the CMC via serial connection to properly set up the serial connection to the blade! If you enter this via iKVM or SSH (network connection), the serial connection will not persist over a server reboot and the connection must be set up again.
Once you have connected to the CMC via serial connection, use your favorite serial communications program (older Windows OS will have the Hyperterminal program, but many programs, such as Teraterm, Putty, and others are perfectly fine)
As you can see below, you will first be prompted to the username and password to obtain Root access – enter your superuser root access username and password.
You will then be at the "$" prompt as noted below.
Enter the following command: "Connect –b server-"x""
- There is a space between "connect" and "-b". There is NOT a space in "server-x"
- "x", in the example is the slot number of the server you want to debug.
- In the M1000e chassis has slots for 16 single-height blades, or 8 double-height blades
- The server number is located on the bezel at the top of the front of the chassis. This is the number you want to enter into the command.
- For a double-height blade, enter the number for the top slot.
Important note 3! You have now established the persistent serial connection to the Dell blade you want to debug. You cannot use the CMC serial connection to communicate with the CMC anymore – it is now connected only to the blade you chose. To clear this connection, you can access the CMC via SSH or iKVM and enter the following command – "racadm racreset". This will reset the CMC – beware – all fans will ramp to maximum while the CMC is resetting (about a minute or two)! This is a great time to blow dry your hair with the fans on the M1000e.
Final Steps -
At this point, you need to properly enable debugging in the operating system on your target. For Microsoft Windows and other operating systems such as Linux, use the following port and settings:
- Serial Port - Com1
- Baudrate – 115200
Please provide any feedback on this article to Thomas_cantwell@dell.com
Supplemental Information -
Microsoft KB article - How to set up a remote debug session using a null modem cable
Setting up Serial Debugging / Console Redirection on Dell 12th Generation Servers