Disk Corruption

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.

Well it been about a week since I last had to run disk warrior on my shared drive. And of course last night the drive would not show up on the desktop of a client computer. So first I ran disk utility it check out ok, so I restarted the mini server and the disk would not show up on the desktop. Ran disk warrior and all was well. I have crashplan running backing up my photos on the disk, also it holds my itunes library. I also have transmission running downloading a few torrents. I been running this configuration for a few years but only the last few months with the server version of os x.
or now I think I will try moving my itunes library to the boot drive ( it runs 24/7 as a shared library), also I had the server app running I think I keep that off for now.

Thanks for the suggestion. I do not have a work XP setup at this time, but I did swap out HDs ( I have a same size backup) of the disk. I just used superduper to clone the disk. It made no difference.

I have been running problem free until last night. Now my disk is mounted at least the programs can access it but it will not show up in the finder, desktop, or sidebar. I restarted checked finder prefs. I can run disk utility on it and it is OK.
Any ideas what is going on????

UPDATE

I made all the invisible items visible, and the drive was on the desktop, set things back to invisible. I ran disk warrior and that made the drive visible.
I'm running 6 macs with many external drives and the only problem I ever have is with the data drive connected to the mac running server. I have even switched disk to eliminate a hardware problem
Just can't figure out this recurring problem,

Les Kern said:

Need to eliminate the possibility it's the disk itself. Seems like a logical next step would be to get another disk even temporarily to test this. I use external drives almost exclusively to back up 20 servers and have never seen this behavior.

Click to expand...

I did copy everything to another drive in another housing and went fron firewire to usb and still the same issue.
I am now thinking it may have something to do with the crashplan program I have running on that data disk.
I may just resign myself to run Diskwarrior once a month