We have a 9 node cluster. 6 nodes are in one data-center and 3 nodes in the other. All machines are Amazon M1.XLarge configuration.
Datacenter: DC1 ========== Address Rack Status State Load Owns Token ip11 1b Up Normal 76.46 GB 16.67% 0 ip12 1b Up Normal 44.66 GB 16.67% 28356863910078205288614550619314017621 ip13 1c Up Normal 85.94 GB 16.67% 56713727820156410577229101238628035241 ip14 1c Up Normal 17.55 GB 16.67% 85070591730234615865843651857942052863 ip15 1d Up Normal 80.74 GB 16.67% 113427455640312821154458202477256070484 ip16 1d Up Normal 20.88 GB 16.67% 141784319550391026443072753096570088105 Datacenter: DC2 ========== Address Rack Status State Load Owns Token ip21 1a Up Normal 78.32 GB 0.00% 1001 ip22 1b Up Normal 71.23 GB 0.00% 56713727820156410577229101238628036241 ip23 1b Up Normal 53.49 GB 0.00% 113427455640312821154458202477256071484 Problem is that node with ip address: ip11 often has 5-10 times more load than any other node. Most of the operations are on counters. The primary column family (which receives most writes) has a replication factor of 2 in DataCenter DC1 and also in DataCenter DC2. The traffic is write heavy (reads are less than 10% of total requests). We are using size-tiered compaction. Both writes and reads happen with a consistency factor of LOCAL_QUORUM. More information: 1. cassandra.yaml - http://pastebin.com/u344fA6z 2. Jmap heap when node under high loads - http://pastebin.com/ib3D0Pa 3. Nodetool tpstats - http://pastebin.com/s0AS7bGd 4. Cassandra-env.sh - http://pastebin.com/ubp4cGUx 5. GC log lines - http://pastebin.com/Y0TKphsm Am I doing anything wrong. Any pointers will be appreciated. Thanks in advance, Ashish
