A letter I sent to my hosting customers:
An interesting software event in one of three of our email servers reflected events in the news. Last night one of the spam filter servers has a kernel crash that shut down the system. The two backup server automatically handled the load and processed all the email without interruption. But – in some cases it delayed the email by 12 minutes because the downed server wasn’t totally dead.
The server’s kernel shut down but the system drivers and network stack was still functional. The server would still ping and accept connections on all the ports that were normally active. So any server monitoring programs would see the server as alive – but once you connected to the ports – there was nothing behind it to process the connection.
In other words – the server was in a persistent vegetative state – the peripherals were still alive – but the system was brain dead. The kernel had crashed and was not responding.
Eventually we had to make the tough call – and we decided to “pull the plug”.
Anyhow – I thought it was somewhat of an amazing coincidence that this computer failed in a way to mirror a current news story. And for those of us who grasp both issues – it was an amazing parallel.