"but what i get from your advice is ( JW063 -- SAS Controller Card, SAS6/IR ) only can configure 2 TB sata hard disk to be raid 1 and to be shown 1 TB >>>>> is it right ????" No.  A SAS 6/iR can use up to 2TB hard drives.  It also has a maximum BOOTABLE Virtual Disk (array) size of 2TB.  So, you CAN have the following: You CANNOT have the following: "but my case is  i have 4 TB (4 sata hard disk 1TB ) want to configure it to be raid 1 and be shown 2 TB after raid 1" You can't have a 4-disk RAID 1 - a RAID 1 requires only and exactly 2 disks.  A RAID 1 with two 1TB disks will equal only 1TB of total space.  The only way to configure two 1TB drives to show as 2TB is to make it a 2-disk RAID 0.  RAID 0 is dangerous, because if one disk fails, then ALL data on BOTH disks is unusable. This is what you should do: 2x1TB disks in first 1TB RAID 1 for your OS.2x1TB disks in second 1TB RAID 1 for your data/second partition.  
hi all , i have dell server poweredge t110 without raid controller card when i try to configure raid 1 on 2 SATA hard disk   from mother board it configured correctly on motherboard but when i am try to install any OS i found it see them 2 hard disk not one so i go back to mother board i found the raid not configured  1-- i need the boot able system management CD for dell poweredge t110 ?????? i bought raid controller ( Dell SAS 5I Raid Controller UN939 - UCS51 ) when i put it on the server i found it when i start my server but when i press CTRL+C to configure raid but i cant found my sata hard disks 2-- is  ( Dell SAS 5I Raid Controller UN939 - UCS51 ) compatible with server poweredge t110 sata + hard disk  ?????? 3-- if  ( Dell SAS 5I Raid Controller un939 - UCS51 ) not comapatible with my case what is the best raid controller work with poweredge T110 with 4 sata hard disk to make them raid 1
poweredge T110 raid urgent assistance needed