I'll tell you how I did that once. I had a backend of multiple oracle dbs running under Veritas Cluster Server on three Sun Micro T-2000 shiny boxen all nicely racked atop one and other. When getting ready for a maintenance operation on the hardware I went ahead and extended the servers on their rails so they would be in the aisle. Well, whoops! My spotty network wonks decided they could not fit any of the servers with proper sized Ethernet cables, so they all popped out before the servers reached the aisle since they were not as long as the bendy rack cable minder! The primary, secondary, and the VCS heartbeat connections, all gone! :P Good thing this was in a maintenance window and we could recover everything by stopping some services and putting in some properly long cables. Plus it did not damage the server's connectors, and this site was not a high traffic one, so not much visibility. As you can see, something simple and not cared for, and taken for granted caught us out.