Simulate any one of the disks in $/$dev$/$md$5$ array for failure, and note the spare disk being replaced for the faulty

disk.Following SCREENSHOTS required at each stage given below

Aftersetting $1$ disk as failed After failed disk removed After spare disk replaced

$$ cat $/$proc$/$mdstat

$$ mdadm $-$D $/$dev$/$md$5$

$$ mdadm $-$E $/$dev$/$md$5$ disk$\_$failed

$$ ls $-$ld $/$raid$5$;ls $-$l $/$raid$5$;df $-$Th $/$raid$5$

$$ cat $/$proc$/$mdstat

$$ mdadm $-$D $/$dev$/$md$5$

$$ mdadm $-$E $/$dev$/$md$5$ any$\_$arraydisk

$$ ls $-$ld $/$raid$5$;ls $-$l $/$raid$5$;df $-$Th $/$raid$5$

$$ cat $/$proc$/$mdstat

$$ mdadm $-$D $/$dev$/$md$5$

$$ mdadm $-$E $/$dev$/$md$5$ disk$\_$replaced

$$ ls $-$ld $/$raid$5$;ls $-$l $/$raid$5$;df $-$Th $/$raid$5$