I am running into a strange problem on my mini server (2009) running ML server. I have 3 external disk attached to the mini, one is a time machine volume for the mini and 2 macbook pros, another is a 2tb shared data disk, and the third is a backup of the 2tb data disk. The third disk is left off most od the times and I turn it on once a week to clone the data disk with super duper. While the disk is being cloned I may have it mounted on on of the other systems but usually pulling data off. I finding after super duper is finished the mounted disk icon is lighter (like it is being unmounted) If I unmount the disk or restart the client the disk is not available. Same is true if I restart the server. The only way to fix the problem is to run disk warrior on the 2tb data disk and rebuild the directory. All will be fine for a few weeks and then I will have the same problem. The cloned back is always fine. I never had this happen on a client OS X system only on the server setup. I think of only doing the disk cloning when nothing is mounted on a client computer, such as over night. However if anyone has any insight to what is going on I would appreciate it.