I'm trying to figure out if a box is running just a single sda disk
or if it actually has hardware RAID setup and Linux just sees this virtual sda disk which is actually composed of several drives hidden behind the card.

for software raid i know that doing mount command would show something like

/home mounted on /dev/mapper/ddfadasdf34234234234

and for nvidia card it would say something like
/home mounted on /dev/mapper/nvidia_34324234234

but in my case i just see /dev/sda1 mounted on /home

cat /proc/scsci/scsi however see several drives being on the system,
dmesg shows the same. But I only see this one drive when doing mount.
So basically I have conflicting information.

What would be the sure way to figure out if i do have a raid array and
if so what raid level I'm running.

thanks

Linux should see a hardware raid as /dev/sdx where x could be any letter.

At a guess, I am assuming the distribution you installed already had the raid drivers in it for the raid you are running and thus is able to actually query the raid card itself as to what is attached to it. I am not sure on a certain way to check what kind of raid array and raid level you are running on a hardware raid for Linux, likely you would need tools from the manufacturer, one example being MegaRAID from LSI for LSI hardware raids.

so then it's consistent that i see /dev/sdx in /dev with the fact that dmesg reports that i have raid.

thanks for replying

It's no problem, I have had to set up several linux servers with hardware raids before, LSI and 3ware (who are now owned by LSI...). I have also seen a host/fake(adaptec) raid, software raid and on one occasion an embedded raid, hardware raid always gives just a normal device where the other three all seem to give mapped devices on top of showing individual devices in /dev/ for mapped devices and all hard drives.

I should have put earlier, the reason for this is that with hardware raid, the raid controller is on the raid card itself and all raid processing is handled by the raid controller. On the other hand for software, embedded and host/fake there is no hardware raid controller and the raid processing is passed on to the CPU. There maybe mobos with hardware raid controllers on them but I am yet to see them, if they ever come around, hardware embedded raid would be some what nice. however given that most decent hardware raid cards seem to cost as much, if not more then most mid-high end motherboards...

anyways, naturally due to the way Hardware Raid works, it's a lot more efficient as it adds no real additional load to the CPU and gives the best performance ratings. I would advise myself, to only ever use Hardware or Software raid, host/fake has caused me issues in the passed is not really any better then software raid, I generally haven't dealt with embedded raid but it's effectively the same as host/fake raid.