I think the "Owns" calculation isn't taking racks into consideration. The fact that you aren't alternating racks (availability zones, with EC2Snitch) is what is causing the imbalance. I suggest either using the same rack for all nodes (preferred) or alternate your racks/AZs: 1b, 1c, 1d, 1b, 1c, 1d, etc.
On Thu, Oct 31, 2013 at 1:12 PM, Ashish Tyagi <tyagi.i...@gmail.com> wrote: > 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 > -- Tyler Hobbs DataStax <http://datastax.com/>
