How to check the RAID configuration on Linux/Unix systems

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Linux based systems support both Hardware and Software based RAID systems. So there are times that we want to check the RAID configuration through the operating system. With Linux this is possible to analyze the configuration with the help of mdstat file.

So, to check the RAID configuration you can simply cat the following files;

 

  • cat /etc/mdadm.conf
  • cat /proc/mdstat

Once the above configuration is analyzed, you will end up with the following specific results;

  • md125 – RAID device file name
  • active raid10 – RAID type
  • sde3[3] sdb3[2] sdc3[1] sdd3[4] sda3[0] – RAID device named /dev/md125 made of five partitions (also known as “component device”)
  • [UUUUU] – Shows status of each device of raid member disk/partition. The “U” means the device is healthy and up/running. The “_” means the device is down or damaged

If you want to determine whether a specific device is a RAID device or a component device, you may execute below;

  • mdadm –query /dev/DEVICE
  • mdadm –query /dev/md125
  • mdadm –query /dev/md12{5,6,7}

If you want to see info about component device named /dev/sdd3, run:
Example: # mdadm –examine /dev/sdd3

How to change the root password on Mac OS

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In brief the steps are as follows;

  • log in to the macOS Unix server using ssh or console or terminal
  • Open a shell prompt/terminal and type the passwd command to change root password

ssh [email protected]

user$ sudo passwd root

First you need to type the password for the user. After that the passwd command asks for the new password, which you will have to enter two times:

The next time you log in to a macOS Unix server, use the new password for root user.