Thanks for both of you guys.

1) yes you want to rebalance to maintain as wide spread of data as possible, new TDEVs that will be build will not be solely concentrated on the new spindles only but actually spread over the existing spindles in the pool which should equate to better/consistent performance.

start balancing on pool type=thin;

2) if you don't rebalance newly build TDEVs will only reside on the new drives.

3) it runs as a background process giving I/O priority to host access, i've rebalanced my pool a couple of times now, no issues to report.

Depending on the level of Enginuity code on the storage and Solutions Enabler, you can set to "auto rebalance"... If you don't balance, severe performance could result. The syntax is in the "Solutions Enabler Array control's guide", plus emc247811... Advise searching knowledgebase for related information, as well as go to PowerLink and search in White Papers for: "Best Practices for Fast, Simple Capacity Allocation with EMC Symmetrix Virtual Provisioning". Hope this helps you get started..

I'm not able to see emc247811 can you pls paste the description over here...Thank you.

Thank you.I will look into the papers.

I am looking into why that solution doesn't show up. However, between the white papers and Solutions Enabler Array control guides, you should be all set there..