LUN or Logical Unit Number is basically a Computer Storage term that is used to specify a logical unit. LUN can be used with any device that supports read/write operations. LUN is not associated with Linux, instead, it is with storage, so, Linux could be installed in that machine.
If you wish to learn Linux and want to get certified, check out the Linux course from Intellipaat. Also, watch the following video on Linux tutorials for Beginners.