The question is too vague and not enough informatioj is know to give you anything other than the standard answer, which is “DEPENDS”
Depends on what your DR plan is.
If you are taking some tapes to anotehr location to see if you can rebuild your database, the end users should not be effect, so no need for notification.
If you are going to do this with your production box, the users must be notified because by definition with a DR, you are rebuilding your data base and thuse would inhibit users from entering current data.
What are the steps in your plan?
Are you trying to restore from a previous time periond and then have the user rekey information?
Are you switching over to a new box and are testing the switch over of all input and output devices/Comm lines?
If you care to provide more information regarding what your steps are, I beleive there are many here that can give you feedback.
another view point …
We always notify our users when we go offsite for D/R testing – so they know we won’t be at work. And since we also test our ability to connect to the outside world from our D/R test location we contact those other data centers that we communicate with so they will know that we are testing and to be prepared to hook up to us at our test location.
I would think your users would be happy to know that you have their best interests at heart and that you are testing your D/R plans.
And remember what they say about disaster recovery … the recovery was a disaster
If something goes wrong, how many people will be affected and how many staff do you have working in your helpdesk department? Could you or do you WANT to handle all the calls? If not, definitely inform!