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I have an IBM blade server and we've installed RedHat Linux on the machine.

How can we check if we have both disks running as a mirror, or if everything is only running on a single disk? What commands can I use to discover this?

Diana

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Use the cfggen utility to manipulate the onboard RAID controller from Linux.

cfggen 0 status will show you what, if any, RAID volumes you have.

As a quick check, if you have a mirror, sda should have a Vendor/Product ID of: LSILOGIC Logical Volume.

With the onboard controller, the raw disks behind the mirror are also exposed to the OS via sg devnodes. See the output of lsscsi -g to find what they are.

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If it's hardware RAID as I suspect, your RHEL will only see a single disk to the OS side.

If you don't yet have any production stuff running on the server, just go ahead and physically test that thing. Remove one disk, see if your server continues working. Put disk back in, remove another disk, see if it still works. Anyway if during production one of your disk goes bad, you'll encounter this little test.

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  • sorry but I need Linux command to check , I dont have access to the blade machine – Diana Aug 4 '11 at 12:02
  • did you have idea how to check with some linux commnad if my configuration is mirror or not? – Diana Aug 4 '11 at 12:54
  • As said, it's likely that he hardware RAID controller abstracts away the separate disks and shows only a single HD (which in reality is your RAID array) to the OS. Only way is to find some vendor-specific RAID controller utility which would show you the controller status. – Janne Pikkarainen Aug 4 '11 at 12:59
  • As a quick guide to whether or not you've got software mirrors in place, the output of df -k and cat /proc/mdstat can be most helpful. – MadHatter Aug 8 '11 at 14:21

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