Thank you Dev Mgr and Chris for your replies, i have come up with the better solution, i have taken my OS image from Acronis and put it some where on network, Change Dell 2850 BIOS Option from SCSI to Raid Enabled. go into array manager by Ctrl+m,  config server for raid 1 and initialize the array it will format my hard disk, boot server from acronis backup and recovery with universal restore, browse my image from network and restore it with universal restore option enabled, after restoring restart my OS and OS  detected drives for Dell PERC 4e/DI Raid Controller. OS is UP and Running Fine......  :-)  hope this will help you people. regards, Adeel Ahmad
hi, sorry if somebody post it already, i have dell server 2850 which is currently in SCSI Mode with single SCSI hard disk and windows server 2008 is running on it with some applications, i want config raid 1(mirror) on it by adding an extra SCSI hard disk into the system without losing my old OS. its there any way i can do it. one thing i know when we go from SCSI mode to Raid Enabled, and Config Raid 1 we have to initialize array, which will format data. which make me think there is no way to do that. i have come up with idea, but not sure it will work or not can some body comment on that. what about if i take my current OS image from Acronis or some other tool, and format Hard by adding them into Raid 1 array, and restore Image into Raid Volume. will it work???  Thanks for your replies and sorry i said something wrong as i am not an expert.
Add Preloaded OS hard disk into an Raid 1 Array without losing data