A few days ago I had a terrible experience. The server I manage has two virtual servers. One is the domain controller, while the other is just the Antivirus server and spam filter for Ms Exchange.
In the morning, I arrive early at the office, smiling as usual (that's almost a lie, but sounds professional). A few minutes later a colleague enters my office: "The telephone is not working." I check mine and it's completely dead. After a second my pc is dead as well: a power outage!
I run to the server room and I see that the UPS is dead as well. The server is just booting up. The UPS somehow is now bypassed.
I've configured the server and related virtual servers, so that when the server restarts, everything will be up and running in about 15 minutes. That's because I installed Ms Exchange on the real server, while the domain controller is a virtual machine; I just tricked Exchange services to start a little bit later - just when the dc is ready... (but that's another story).
So, I switch on the monitor just to check how things were going. After a while, all the services start and the dc is fully functional. Just to be sure, I check the antivirus server (which is a Windows 2000 server by the way). Some system files are corrupted and the virtual machine can't boot.
That's when you realize that virtualization is a great idea. I shut down the machine, move a back up file and restart the virtual server.
"A few minutes and everything will be ok!"
That's only if you have a fairly recent backup! And - sob - I hadn't... All the latest configurations on the anti spam program are lost. But then I realize that I can install another virtual hard drive with the corrupted operating system... "That's an idea!"
Basically the virtual machine started with a perfectly working backup, while the corrupted one was added as an additional virtual hard disk. I looked for the corrupted config files, replaced them, switched again virtual machines files, and everything was up and running perfectly!
Just after that, I switched off the virtual machine and made a backup copy... you know... just in case!
Well, virtualization can really save you from a lot of troubles. For the PBX, I just had to call technical support: the PSU was completely burned. And the UPS seemed to have the battery pack completely exausted - possibily it needs to be replaced.
Just another morning at the office.