What is the failure rate of servers being moved physically from one location to another?

You don't mention how long the drives have been in use, how old they are, etc. The longer they've been running 24/7 the greater the chance they won't spin back up.

The transport could be rough on them if you're talking about a long haul over potholed roads.

If you're very worried...

Have backups to tape. Backups that can restore from bare metal.

Buy some spare drives. You will most likely have a few die. If not now, definitely down the road :-)

Pack everything very well, but label and remove each and every drive and pack them separately and transport them separately from the servers/racks. Hand-transport them in your car with foam lined cartons, then plug them all back into the proper server and drive slot, so that hopefully they'll take less punishment in your car than in the back of a transport truck. Some would probably argue this is overkill, however.

Travel with the backups and servers separately. An accident or incident shouldn't kill both your data systems and your backups.

Not enough data. How are they being packed? How bumpy is the road?

If you're using reasonable caution, you probably won't see any problems, with reasonably new servers, but you can always lose a hard drive. I'd make sure my backups were up to date, and the servers were well padded and secured.

@lombardm

I'd be worried too. Almost all of those things can shorten the life of your HDDs. Definitely make sure of your backups. Still, in all likelihood, this will only (again) shorten the life of those drives. Most of them are going to weather it fine.

How old are the servers? We had some old (5 year) video storage servers that had about a 10% hard drive failure rate when we had to just shut them down for a few hours for power maintenance. We figured the 24x7 fatigue on the hard drives finally caught up when they were spun down and then fired back up. Something we definitely didn't expect from performing a soft shutdown/startup.