Data usage is based on the pool; its a logical construct.  The pool will be balanced based on the data dev's placed in it.  You can easily create multiple pools with the data dev's you have.  You have a valid concern in that when you create multiple pools how do you create them?  Do you merely use data dev's that are available and wind up with multiple pools service by the same phsyical disks; or do you create a boundary by placing disks into a disk group to create a pool serviced by a portion of the physical disks available.   Its the classic "it depends on what you are doing" answer.   I prefer to create a pool based on physical disk boundaries by placing disks into select disk groups.  The arguement is you normally get more predictable performance by designating resources to something versus optimal performance that can vary by "going wide" and sharing resources more.
I have 1440 TDAT's configured in the VMAX(450 GB, 15000 RPM drives).  What is the best practice I need to follow when adding them to the thin pool ? Do you go in a sequence or pick TDAT devices from specific DA's to spread them out ?   I am referring to "Best Practices for Fast, Simple Capacity Allocation with EMC Symmetrix Virtual Provisioning Technical  Note" on Page 20. According to that example, it's basic configuration.  TIA  -Shyam
Adding TDAT's to Thin Pool