I removed the HDD, and put it back in and let unRaid built the data. Data rebuilt went successful.

 

Diagnostic is attached

tower-diagnostics-20150922-1128.zip

Wow, what an awful mess!  I cannot believe you have been able to run as well as you have!  Your SAS disk controller is badly malfunctioning.  It's an 88SE9485 (Marvell [1b4b:9480]) which I believe is the SAS2LP card, known elsewhere as a real troublemaker in v6.  Your syslog is even MUCH worse than the others have been suffering through, with that card.  All I can advise for now is to quickly find a replacement.

 

The good news though is that your drives are probably fine.  I did not examine every bit of your syslog, but at least 2 drives (Disk 5 and Disk 6) were regularly dropping off and returning, often with new addresses and ID's, fatal for unRAID operations.  When it's multiple drives like that, it's almost always not the drive's fault, but the controllers they are attached to, and both are on the SAS card.  What's worse is that the drive/controller problems were causing huge problems for the kernel too!  Normal operation was impossible, almost from the very start of this syslog.

  Isint there somehow i could still use this SAS Card? After a lot of study and suggestions from members on this forum i had to go great lengths to pro-cure this card... and now i am been told it dosent support unRaid. I was earlier told this card worked best under unRaid environment!

 

Could i just connect the HDD in question directly on the mobo sata ports instead of the SAS card to fix the problem?