Hi, Ive been trying to understand how the Balancer class works. I know the basics about the threshold guidelines and the general motivations of running the balancer.
I had a few questions about block migrations: 1. I noticed there is a Source and Target, but there is also a ProxySource. I havent been able to grasp the conceptual difference between a source and a proxy source 2. I'm also having trouble understanding the actual mechanics of a block being relocated from one datanode to the other. I understand that the communication with the namenode occurs to change metadata of the block being relocated accordingly, but have not understood what does the actual copy of the block itself. I'd appreciate it if some developer can shed some light on this for me and point me in the right direction (like which classes/functions I should be looking at to understand this) Thanks, -- Amit Gupta
