Hard Drive is not detected in RAID 1

Hello,

I have HP Proliant ML 150 G5 Server in which RAID 1 is configured with two hard swable SATA Harddrive 250 GB But right now i want to fix one new SATA 250 GB hard drive for scheduled backup but the problem is that, when i put the hard disk in HP server and restart the system then the new hard disk is not detecting.

Hard Disk scenario is like that: 1st hard drive in 1st bay and the 2nd hard drive in 3rd bay so these both are configured in RAID 1 which working fine.But when i inserted the 3rd hard drive in 2nd bay and restart the system but nothing detect in Disk management.

so how i can detect the 3rd hard drive for schedule backup in the above scenario pls?

Any help will be highly appreciated.

Thanks and Regards,

Akram Network Administrator.