If you are looking for time-series databases based on Cassandra that you can use with Graphite, check out
Cyanite: https://github.com/pyr/cyanite and https://github.com/brutasse/graphite-cyanite
KairosDB: https://github.com/kairosdb/kairosdb and https://github.com/kairosdb/kairos-carbon and https://github.com/Lastik/KairosdbGraphiteFinder