I have a HP ProLiant DL360 Gen9 server which has three physical 900GB HDDs. Those three HDDs are in some sort of hardware RAID setup. RAID controller is HP 3239 and it uses hpsa driver. For OS it represents itself as a 900GB sda device. Now if I check the RAID level with # cat /sys/class/scsi_disk/0:0:0:1/device/raid_level, then it shows RAID 1(1+0). Is this some sort of RAID 10 with three physical drives? Or is it triple mirroring? What is also interesting is that while activity LEDs of two drives blink in sync, then the third drive shows very little activity. Last but not least, I am not able to install additional software on this server because it is Linux based special appliance.

  • 1
    What type of "special appliance" is it? – ewwhite Mar 30 '16 at 14:04
  • It is an AlienVault OSSIM. – Martin Mar 30 '16 at 19:01

HP DO do a form of R1 where it writes to three disks instead of 2 but it's rarely used, more likely the third disk is set aside as a hot-spare - or it's not being used at all!

  • Looks like that third HDD is a dedicated spare drive Does this mean that when one of the drives in RAID1 fails, then this spare drive will automatically take its place? – Martin Mar 30 '16 at 19:50
  • 1
    Yes, exactly that. – Chopper3 Mar 31 '16 at 7:09

It looks like raid 1 with a hot spare. The HP array tools should be available for Linux from the HP website, depending on distro.


See if the system has the hpssacli command installed.

  • If so, you can run hpssacli ctrl all show config to get the configuration of the array.

  • If this command is not installed, you may want to install it... depending on the specific operating system being used.

  • You can also reboot and view the array configuration from the BIOS utility or by launching the F10 Intelligent Provisioning menu.

  • If you have access to the server's ILO4 interface, you can get the array configuration from that by clicking on the "Storage" menu.

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  • Thanks! As I did not want to install additional packages to this appliance, I finally reloaded the server and looks like this is a dedicated spare drive. I guess RAID 1(1+0) in output of cat /sys/class/scsi_disk/0:0:0:1/device/raid_level means that? – Martin Mar 30 '16 at 19:55
  • 1
    No, it does not mean that. It means RAID 1 (or 1+0). The spare is not visible to the OS. – ewwhite Mar 30 '16 at 20:31
  • Ok, I see. The spare is visible only to RAID controller which automatically uses this drive if one of the RAID 1 mirror drives fails? – Martin Mar 30 '16 at 22:49
  • 1
    That is correct. – ewwhite Mar 30 '16 at 23:03

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