[RocketRAID 2760 PCI-Express 2.0 SATA III (6.0Gb/s)]

 
Specifications:

• Speed: SATA 3 (6.0Gb/s)
• Ports: 6x Internal Mini SAS SFF-8087
• Slot: PCI-Express 2.0 x16
• Chipset: See Marvell 9485 SAS/SATA Controller Chip

Firmware

• Firmware: 1.3
  • AHCI compatible: No (proprietary driver required)
  • Link: http://www.highpoint-tech.com/USA_new/CS-PCI-E_2_0_x16_Configuration.html
• Driver: 1.2.12.1023 (10/23/2012)
  • rr276x.sys
  • Link: http://www.highpoint-tech.com/USA_new/CS-PCI-E_2_0_x16_Configuration.html

Performance

• SATA III SSD
  • Burst: 481 MB/s
  • Drive: Intel SSDSC2CT180A4
  • OS Tested: Windows Home Server 2011
     
• SATA II HDD
  • Burst: 171 MB/s
  • Drive: Seagate ST3200045AS
  • OS Tested: Windows Home Server 2011
    

• SATA III HDD
  • Burst: 459 MB/s
  • Drive: Seagate ST2000DM001
  • OS Tested: Windows Home Server 2011
    

[Data categorised as Other not Unduplicated]

whats the unusable for duplication

Look at "File Placement Limits" section here.  "http://blog.covecube.com/page/2/"

[SMART info with Sharkoon 8 Bay Raid Station]

Have you tried enabling the  "UnsafeDirectIo"?

 

http://wiki.covecube.com/StableBit_Scanner_Advanced_Settings

[My Rackmount Server]

I have a Norco 4224v1 4U case.

 

CPU: Intel i3-530

MoBo: HP ProLiant ML110 G6

RAM: 4x2GB CORSAIR Vengeance

GFX: Onboard

OS Drive: 180GB SSD, Intel 335 Series (WHS 2011)

Storage Pool: 13x2TB (Seagate ST2000DM001)

HDD Controller card: HighPoint RocketRAID 2760 (All drives connected to controller)

3TB Seagate ST3000DM001 for Server Backup (system drive, and system files) / Client Backups

Drivepool / Scanner