Hi, We are implementing a Kafka cluster with 9 brokers into EC2 instances, and we are trying to find out the optimal number of partitions for our topics, finding out the maximal number in order not to update the partition number anymore. What we understood is that the number of partitions shouldn’t affect the CPU load of the brokers, but when we add 512 partitions instead of 128, for instance, the CPU load exploses. We have three topics with 100000 messages/sec each, a replication factor of 3 and two consumer groups for each partition.
Could somebody explain, why the increase of the number of partitions has a so dramatic impact to the CPU load? Here under i paste the config file of kafka: broker.id=3 default.replication.factor=3 # The port the socket server listens on port=9092 # The number of threads handling network requests num.network.threads=2 # The number of threads doing disk I/O num.io.threads=8 # The send buffer (SO_SNDBUF) used by the socket server socket.send.buffer.bytes=1048576 # The receive buffer (SO_RCVBUF) used by the socket server socket.receive.buffer.bytes=1048576 # The maximum size of a request that the socket server will accept (protection against OOM) socket.request.max.bytes=104857600 # A comma seperated list of directories under which to store log files log.dirs=/mnt/kafka-logs # The default number of log partitions per topic. More partitions allow greater # parallelism for consumption, but this will also result in more files across # the brokers. num.partitions=16 # The minimum age of a log file to be eligible for deletion log.retention.hours=1 # The maximum size of a log segment file. When this size is reached a new log segment will be created. log.segment.bytes=536870912 # The interval at which log segments are checked to see if they can be deleted according # to the retention policies log.retention.check.interval.ms=60000 # By default the log cleaner is disabled and the log retention policy will default to just delete segments after their retention expires. # If log.cleaner.enable=true is set the cleaner will be enabled and individual logs can then be marked for log compaction. log.cleaner.enable=false # Timeout in ms for connecting to zookeeper zookeeper.connection.timeout.ms=1000000 auto.leader.rebalance.enable=true controlled.shutdown.enable=true Thanks in advance. Carles
