Dear Alexander; Thanks for your reply but what you are saying could apply in Europe and USA but not in Middle East. I'm using these servers for around 5 years now and I know it's NEC with FakeRaid ; please check these photos https://drive.google.com/open?id=0BzqgoXi9IUMid3pNOXRZOHZuMkU I totally agree with John; NEC sold these servers with fakeraid from LSI as I used to login to LSI Firmware to manage the RAID disks. But when I install Centos 5.X/6.X 64bit; I can see the disks as standalone disks as well as dmraid devices. # dmraid -rD /dev/sda: ddf1, ".ddf1_disks", GROUP, ok, 974608384 sectors, data@ 0 /dev/sdb: ddf1, ".ddf1_disks", GROUP, ok, 974608384 sectors, data@ 0 It looks like kernel issue more than Centos 7 issue as I faced the same issue while installing Debian 8 Please; check this link:- https://bugs.centos.org/view.php?id=9813 https://www.centos.org/forums/viewtopic.php?t=49069 Thanks again for you and John and I hope they will solve this bug as soon as possible