Data centre migration using SRDF

Hi All,

Customer decided to build a new DC (third site), this new DC will be promoted to be the main site and at the end running main site will be considered as DR, current DR site will be decommissioned (after some time)

current setup:

Two sites, site1 (main) and site2 (DR), site1 has VMAX950F replicating to VMAX950F at site2 AND VMAX850F replicating to VMAX850F at site2.

Scenario:

Powerup/Initialize PowerMAX8K at site1 and configure concurrent SRDF/adaptive copy so VMAX950F and VMAX850F will replicate to PowerMAX at site1 AND VMAX boxes ate site2 (R11 from site1 VMAX950F/VMAX850F  TO  PowerMAX at site1(temporarily)  and VMAX950F/VMAX850F at site2)  

Procedure:

Split replication between site1 VMAX boxes and PowerMAX after initial copy completed then shutdown PowerMAX, move it to site3, powerup and resume replication.

At a certain time we will failover and change personality so PowerMAX will be R1, VMAX boxes at site1 will be R21 and VMAX boxes at site2 will remain as R2(for a while)

Questions:

1-SRDF will change from concurrent to cascaded after failover and swap personality, site3(new site) will be R1, site1(currently the main site) will be R21 and site2(currently DR) will remain as R2, Is this supported scenario? to change from concurrent to cascaded? (Not for all volumes, some will remain as concurrent and will be moved in phases)

2-When we split the replication between VMAX boxes and PowerMAX at site1 and shutdown PMAX in order to move it to site3, What are the factors that need to be checked before planning for the relocation? DSE, time duration...etc, any consideration or recommendations?

forget to mention, the connection will be DWDM connection between all sites.

Thanks in advance.