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Manageability on HP Itanium Linux Servers

I've just been using and exploring the Management Processor (MP) on an HP rx2600 Linux Itanium server. It's really slick. I'm very impressed.

The MP is basically a daughterboard containing an ARM7 embedded processor, which has a serial and 10/100 ethernet port, and a simple VGA controller. It's tied into the main motherboard through I2C, PCI and other (?) connections, so it can see what's happening but is independent from the main processors. The board has a little bit of RAM, ROM, and NVRAM.

This is kind of similar to the debug monitor features you might have encountered on Sun machines or Macs, but putting it on a separate board has a few interesting features. One is that the MP is active whenever the machine has mains power, even if the main processors and fans are shut down, and it can bring it back up. Another is that the MP ought to be less intrusive with the operation of a machine: a debug monitor typically halts the whole machine while its active, whereas this allows the machine to keep running.

An enormously cool thing about the way the MP is implemented is that its console appears to Linux as a regular UART. Simply by booting with console=ttyS0 you can get all the Linux boot information routed through the management processor. That in turn allows a few interesting possibilities: sending them to a serial console of course, or across a telnet connection, or logging them in NVRAM so they can be inspected later. Similarly if the kernel panics, you get that information in a telnet window where it can be easily saved, not on a screen where it has to be copied down.

Other nice features:

• Turn on an attention LED, so you can find the machine in the machine room.
• View a text representation of the front panel LEDs.
• Reboot, power up or down the machine.
• Get detailed diagnostics on every part of the machine, and a record of hardware events.
• View console logs.
• Share sessions between several adminsitrators.
• Induce a kernel dump. ("Transfer of Control" in HP's language.)

One downside of the current implementation is that the network interface is not active by default, and you apparently can't get into it through the VGA console. So to enable all this functionality, as far as I can make out, you have to start out with a null modem connection, which can be a bit difficult. But there may be some way around that that I just have not discovered yet.

I was at first a bit confused about the interaction between the MP and the EFI (Extensible Firmware Interface) pre-boot system, but it looks like they're more or less separate and complementary.

I suppose these features are taken for granted by the high-end Unix audience, but this is the first time I've personally seen them in a machine that is within shouting distance of i386 bang/buck, at least for some applications. Not needing to traipse down to machine rooms to work out whats wrong, and being able to get accurate information about a problem without needing to reproduce it or suspend operation should be a boon for serious users.

All this, and it also keeps my feet toasty warm!

posted Thu 31 Jul 2003 in /computers/hardware/rx2600 | link

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