What's the best modeling approach for ordering events by date?

[Guillermo Winkler]

I have a huge number of events I need to consume later, ordered by the date
the event occured.

My first approach to this problem was to use seconds since epoch as row key,
and event ids as column names (empty value), this way:

EventsByDate : {
    SecondsSinceEpoch: {
        evid:"", evid:"", evid:""
    }
}

And use OPP as partitioner. Using GetRangeSlices to retrieve ordered events
secuentially.

Now I have two problems to solve:

1) The system is realtime, so all the events in a given moment are hitting
the same box
2) Migrating from cassandra 0.6 to cassandra 0.7 OPP doesn't seem to like
LongType for row keys, was this purposedly deprecated?

I was thinking about secondary indexes, but it does not assure the order the
rows are coming out of cassandra.

Anyone has a better approach to model events by date given that
restrictions?

Thanks,
Guille