What you want is:
agent.sinks.flumeHDFS.hdfs.rollCount = 0
agent.sinks.flumeHDFS.hdfs.rollInterval = 0
agent.sinks.flumeHDFS.hdfs.rollSize = 10000000
agent.sinks.flumeHDFS.hdfs.batchSize = 10000
From the chimney documentation
hdfs.rollSize: File size to trigger roll, in bytes (0: never roll based on file size)
rollInterval 2000, 2000 , .
, batchSize , HDFS, . , , , , , HDFS.