How is netflow data supposed to be rotated?

[deviantintegral]

I re-enabled netflow about a month ago, and ever since it's been slowly growing in disk use. This is on a home connection, so it's not /that/ much traffic to log. flowd and flowd_aggregate are both running:

root@blackbox:/var # service flowd status
flowd is running as pid 36517 36532.
root@blackbox:/var # service flowd_aggregate status
flowd_aggregate is running as pid 42215.
root@blackbox:/var # du -sh log/flowd* netflow
3.6G   log/flowd.log
 11M   log/flowd.log.000001
 11M   log/flowd.log.000002
 11M   log/flowd.log.000003
 11M   log/flowd.log.000004
 12M   log/flowd.log.000005
 11M   log/flowd.log.000006
 11M   log/flowd.log.000007
 11M   log/flowd.log.000008
 11M   log/flowd.log.000009
 11M   log/flowd.log.000010
5.3G   netflow

I'm going to have to reset the data manually as I'm almost out of disk space. My understanding is simply running flowd_aggregate should be enough here. Is there anything else to check?

[deviantintegral]

One more bit - I just noticed that the UI isn't showing any data for the past 2 weeks. However, disk use has been steadily increasing in that time.