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Benedict commented on CASSANDRA-6746: ------------------------------------- But that's the opposite issue, surely? They found disabling DONTNEED was good - for exactly the same reason, that their OS was obeying it unequivocally - not that _enabling_ it (for the opposite situation, flushing) was beneficial. > Reads have a slow ramp up in speed > ---------------------------------- > > Key: CASSANDRA-6746 > URL: https://issues.apache.org/jira/browse/CASSANDRA-6746 > Project: Cassandra > Issue Type: Bug > Components: Core > Reporter: Ryan McGuire > Assignee: Benedict > Labels: performance > Fix For: 2.1 beta2 > > Attachments: 2.1_vs_2.0_read.png, 6746-patched.png, 6746.txt, > cassandra-2.0-bdplab-trial-fincore.tar.bz2, > cassandra-2.1-bdplab-trial-fincore.tar.bz2 > > > On a physical four node cluister I am doing a big write and then a big read. > The read takes a long time to ramp up to respectable speeds. > !2.1_vs_2.0_read.png! > [See data > here|http://ryanmcguire.info/ds/graph/graph.html?stats=stats.2.1_vs_2.0_vs_1.2.retry1.json&metric=interval_op_rate&operation=stress-read&smoothing=1] -- This message was sent by Atlassian JIRA (v6.2#6252)