add error when writing to cassandra
add error when writing to cassandra

raintank/raintank-metric,raintank/raintank-metric,raintank/metrictank,replay/metrictank,raintank/metrictank,raintank/metrictank,replay/metrictank,replay/metrictank,replay/metrictank,raintank/raintank-metric,raintank/metrictank