You can run RAID6 w/no spares.  My suggestion is not to change this, unless you purchase one or two cold spares for that location.  If you lose one drive, performance won't be impacted near as much if you lose two drives.   While right now it's only replication but in case of a real emergency that could become your active site.   You can only set no spares at the CLI.   If you haven't done so already, suggest upgrading to 5.2.2 first.  Support16> mem select Support16-0 raid-policy ?         - Configures RAID set type to one of the following: raid5,                           raid6, raid10, raid50, raid6-nospares, raid10-nospares,                          raid50-nospares, raid6-accelerated. Support16> mem select Support16-0 raid-policy raid6-nospares Regards, 
Ive got a ps4100e at a DR location doing replication only.  It has 12 3gb drives.  I want max storage capacity as its only doing replication.  I set it up with raid 6 but its only giving me about 24tb.  I notice it still has a hot spare and there doesnt appear to be any way to change it.  what is the point of raid 6 over raid 5 if its still going to keep a hot spare?  Is there any way to get it to actively use all 12 drives and have no hot spares? Thanks.
hot spare w/ raid 6 on a ps4100e 