Is you client balancing between the two nodes ? Heavy writes at CL ONE could result in nodes dropping messages and having an unbalanced load.
Are you sure there is nothing else running on the machines ? Just for fun have you turned off GC logging to see the impact ? Is there swapping going on ? Cheers ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 17/07/2012, at 5:12 AM, feedly team wrote: > I am having an issue where one node of a 2 node cluster seems to be using > much more I/O than the other node. the cassandra read/write requests seem to > be balanced, but iostat shows the data disk to be maxed at 100% utilization > for one machine and <50% for the other. r/s to be about 3x greater on the > high i/o node. I am using a RF of 2 and consistency mode of ALL for reads and > ONE for writes (current requests are very read heavy). user CPU seems to be > fairly low and the same on both machines, but the high i/o machine shows an > os load of 34 (!) while the other machine reports 7. I ran a nodetool > compactionstats and there are no tasks pending which i assume means there is > no compaction going on, and the logs seem to be ok as well. the only > difference is that on the high i/o node, i am doing full gc logging, but > that's on a separate disk than the data. > > Another oddity is that the high i/o node shows a data size of 86GB while the > other shows 71GB. I understand there could be differences, but with a RF of 2 > I would think they would be roughly the equal? > > I am using version 1.0.10. >
