hi guys

I know my Linux Servers have RAID...

but I want to know
1. Can I find RAID level?
2. how to find Disk information...I mean if it's not possible to get RAID Can I get how many hard drives and the real size?

is does not show me if that is 1 physical hard drive or 2 Hard Drives in RAID 1.

thanks a lot

Presumably you're speaking of hardware RAID. (Your software RAID could be seen with mdadm.) Since the hardware RAID reports logical units (LUNs) rather than disks to the OS you wouldn't be able to tell what makes up the LUN as the OS thinks that IS a disk.

You really wouldn't want it to see the individual disks anyway since the chances you'd overwrite part of your LUN by accessing one of its component disks are fairly high simply because it would be so easy to do.

To know what made up the underlying LUNs you'd have to examine the hardware that presented them. For example if it were a Dell PERC adapter you could see the disks using Dell's OpenManager or by going into the PERC's configuration during boot. If it were an external array presented via Qlogic or Emulex fibre cards you'd have to go to the array's own utilities to determine this information (e.g. EMC Navisphere to see EMC's Clariion arrays). Its possible that whatever your hardware is offers a command line that can be run from within the OS but that usually requires you to have installed the software on top of the OS.

P.S. Multipathing usually used for external arrays for redundancy makes it even more fun because you see a "disk" for each path to the LUN. That is to say in a multipath arrangement of 4 paths /dev/sda, /dev/sde, /dev/sdi and /dev/sdm might all refer to the same "disk" (LUN).

nice to know I was thinking that maybe there was a way on linux to get number of disk o disks details