I'm seeing lots of ParNew messages which is affected performance, along the lines of:
INFO 17:54:18,567 GC for ParNew: 1522 ms, 69437384 reclaimed leaving 979692384 used; max is 4424663040 INFO 17:54:22,567 GC for ParNew: 1989 ms, 69323576 reclaimed leaving 981439840 used; max is 4424663040 INFO 17:54:26,187 GC for ParNew: 1337 ms, 69447160 reclaimed leaving 983903040 used; max is 4424663040 INFO 17:54:29,489 GC for ParNew: 861 ms, 69507336 reclaimed leaving 986200344 u sed; max is 4424663040 INFO 17:54:32,238 GC for ParNew: 954 ms, 69245912 reclaimed leaving 987667920 u sed; max is 4424663040 INFO 17:54:36,053 GC for ParNew: 1242 ms, 69501648 reclaimed leaving 989972496 used; max is 4424663040 and this is affecting performance. This is on an 8Gb 4xCore machine with a 4Gb heap and mmapped i/o. KeyCaches are set to defaults and RowCaches are turned off. If I flush, then restart cassandra these go away and performance goes back to a decent level for a certain time until these crop up again. Obviously this is something to do with memory pressure but I'm not sure what. When I restart the node I presume that more requests are hitting the disk, but from a client perspective this ends up giving much better performance than when under the GC storm. Are there some settings I can tweak to ensure this doesn't happen and perhaps direct more queries to disk? -- Maybe she awoke to see the roommate's boyfriend swinging from the chandelier wearing a boar's head. Something which you, I, and everyone else would call "Tuesday", of course.
