Global Spare or Dedicated Spare?

Global hot spare:
                              A global hot spare is not assigned to a specific logical drive, it will protect any redundant logical drive on the controller. (RAID 0 logical drives and simple volumes are non-redundant and are not protected by hot spares.) You can designate a global hot spare before or after you build logical drives on a controller.

Dedicated hot spare: 
                                   A dedicated hot spare is assigned to one or more specific logical drives and will only protect those logical drives. A dedicated hot spare that is assigned to protect more than one logical drive is called a pool spare. You must create the logical drive before you can assign a dedicated hot spare to protect it. 

Clearing disk space when a file is deleted but still consuming space

[root@test01 /]# lsof  | grep deleted

Once you are sure of the culprit file, specifically grep that in lsof.

[root@test01 /]# lsof  | grep deleted | grep rabbit@test01.log-20151108
beam.smp   43563      root   10w      REG              253,0 29471244165          1371295 /var/log/rabbitmq/rabbit@test01.log-20151108 (deleted)

Find the entry in /proc/<pid>/fd/ that corresponds to the filehandle (for above case:)

[root@test01 /]# ll /proc/43563/fd/10

Now, just cat /dev/null into the fd:

[root@test01 /]# cat /dev/null > /proc/43563/fd/10

And we are good to go :-)