I am trying to deliver an attractive and consistent TCO with FAST.  My thoughts of best practice with the CX and NS with regard to FAST running flare 30, are to use the same Raid groups for storage pools.

The price of EFD/Solid State drives somtimes prices customers out of solutions.

I would like to use mixed raid groups.  For instance at the smallest entry point for my storage pool would look like this.

Tier 1 - EFD - Raid 1/0 or Raid 5(2+1). 

     During failure in raid 5 using SSD rebuild time is almost nill since the speed of SSD helps rebuild time.  Should I have concern with a 2+1 Raid 5?

Tier 2 - SAS  Raid 5

     300GB, 600GB drives

Tier 3 - NL-SAS Raid 6

    2TB Drives, No hot spare on Raid 6

My Question is do I have to use the same Raid groups and Can I use Rais 1/0 at the top Tier 1 and drift towrds Raid 5 Tier 2, and then Raid 6 Tier 3??

What do you all think????

Thanks in advance and look forward to all thoughts.

Ed Lyman