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Background

I accidentally forgot to unplug a server's power when pulling a card even though the system was powered down at the OS level.

Unfortunately doing so seems to have corrupted the system's BIOS and the IPMI/BMC BIOS. It also seems to have fried the on-board video.

This has occurred on a Supermicro motherboard which is why I tried re-flashing the main BIOS and IPMI BIOS. Reflashing the main BIOS went without problems and no errors are shown in any BIOS logs.

I thought hotplug technology should have meant that I could physically pull a card while it is running. Searches of the internet seem to imply that.

Questions

In what cases does hotplug really mean hotplug? and Do the cards themselves need to support this feature specifically?

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I've never heard of having a server get corrupted because its power cord wasn't unplugged... but I guess there's a first time for everything –  Mark Henderson Mar 5 '12 at 23:29
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Maybe i supports hot-plug, but not hot-unplug! –  devicenull Mar 5 '12 at 23:42
    
@MarkHenderson, I have seen a couple systems get broke when swapping parts, while it still had power, but was 'off'. It is pretty rare though. –  Zoredache Mar 5 '12 at 23:59

1 Answer 1

As a general rule, you should never hot-swap PCI/PCI-X/PCIe cards unless they expressly state support. You can easily damage the card or motherboard by pulling or inserting the card at an angle.

That disclaimer aside, I've had luck hot-swapping NICs, as long as they weren't active (uninstalled drivers or disabled the device). I'd never dream of pulling anything that draws as much power as video, however, or something system-critical like a drive controller, without explicit support.

The trick is that you need to be able to insert or remove the card straight, to avoid shorting any of the fingers. That's most likely what happened in this case, the card was removed at an angle (as we tend to do when the machine is off), and shorted the board.

The difference between a "hot-plug" card and a non- is that the "hot-plug" cards have drivers and hardware designed to cut power on request, thus letting you safely remove the card. In the case of a NIC, disabling the device usually cuts power.

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