I have given 10GB RAM in cassandra.in.sh.
-Xmx10G \ i have increased KeysCachedFraction to 0.04. i have two different drives for commitlog and data directoy. i have about 3 million rows. what can i do to improve read speed? thanks a lot!
Since 0.5 doesn't have row caching, 10G is probably too much to give the JVM and is hampering the OS cache. Try between 2-6GB instead and see if that helps.