How do I calculate the "Total Usable Storage Size" in clariion -Cx3 20C (I'm little confused here on how to proceed with the calculation)? I have the raw storage size from the disk summary (included the hot spare).I know the used storage size ,calculated from storage group.

I need to calculate the total available storage size = Total usable storage size- Used storage size.

How do you calculate the total usable storage size?

**Note:** Do I need to go to `Array`

> `R click`

> `Bind Lun`

and then look for free capacity under each raid group?

How do I go for celerra?

*I do not have ECC enabled.