Andrey,
I installed 64 bit RHEL 6.1 on B 200 M1 server and do not observe this behavior.
Blade has a LSI raid controller with RAID 0 configured on two local HDDs.The RAID array is listed as sda
# fdisk -l /dev/sda
Disk /dev/sda: 146.0 GB, 145999527936 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 2 501 512000 83 Linux
/dev/sda2 502 139236 142064640 8e Linux LVM
# uname -a
Linux RHELv61-server 2.6.32-131.0.15.el6.x86_64 #1 SMP Tue May 10 15:42:40 EDT 2011 x86_64 x86_64 x86_64 GNU/Linux
# cat /etc/redhat-release
Red Hat Enterprise Linux Server release 6.1 (Santiago)
I did a installation using virtual CD via KVM.
At what stage of installation and where do you observe these virtual devices ?
-Padma