Centera-ECS Migration using Transmission method

Hi Champions,

I have a question on ECS-Centera migration using transmission method. After the application has been cut over to ECS, All the new writes from Application is only on ECS and the reads are first looked in ecs and if not found it reads the data from Centera.

Here is what i find in the Centera ECS migration document  :

Phase 5: Migration

"Due to the concurrent and orderless nature of migration some object may be partially migrated at any particular point in time."

What i am tryinng to undertand is "during the migration phase, when the application requests a read and if it is not found in ECS, does it copy the data to ECS after it is read from Centera ? or does it have to wait for its time to be copied to ECS ?

If there is a documentation on the same it will be great. Any help appreciated !

Thanks,

Sathyaprakash Mohandass