On Thu, Aug 1, 2013 at 12:26 PM, Robert Coli <rcoli@eventbrite.com> wrote:
On Thu, Aug 1, 2013 at 9:35 AM, Carl Lerche <me@carllerche.com> wrote:
I read in the docs that `nodetool repair` should be regularly run unless no delete is ever performed. In my app, I never delete, but I heavily use the ttl feature. Should repair still be run regularly? Also, does repair take less time if it is run regularly? If not, is there a way to incrementally run it? It seems that when I do run repair, it takes a long time and causes high amounts CPU usage and iowait.

TTL is effectively DELETE; you need to run a repair once every gc_grace_seconds. If you don't, data might un-delete itself. 

How is it possible? Every replica has TTL, so it when it expires every replica has tombstone. I don't see how you can get data with no tombstone. What do I miss?