If you create a raid group, that does not impact Auto-tiering as that is only for Pools.  You can have Pools and Raid Groups on the same array - there is no conflict. Just remember to have sufficient hot spares configured. If you're not concerned about performance, just configure a Raid 5 Raid Group with the extra disks (they need to be the same type and capacity). Try NOT to use the first four disks in the array - the Vault drives - you can use these if the usage is a low workload, but be aware that high workload can impact performance. Check HELP in Unisphere for Raid Groups if you need more information.  glen
I am unwilling to forklift another SAN solution just because my gear has a few years on it and wanted some advice on squeezing a few more TB out of my SAN.  I currently have a VNX-5200 with external drive chassis.  The unit was configured with one large storage pool which left four drives unused even accounting for the different hot spare policies.  I also have four empty slots on the external drive chassis.  Is there any problem with me creating a small Raid 0/5 Group from the unused drives along side the existing Storage Pool.  Will that mess up any auto-tiering.  My focus will be on capacity and not performance or even reliability so I would not have a hot spare.  I am sure I am violating a best practice as far as EMC/Dell is concerned but I hate the wasted space and I reaching capacity in the Storage Pool.  If further information is required please let me know and thanks for everyone's time.
Desperate need of quick storage