On Tue, Oct 9, 2012 at 12:56 PM, Oleg Dulin <oleg.du...@gmail.com> wrote: > My understanding is that the repair has to happen within gc_grace period. > [ snip ] > So the question is, is this still needed ? Do we even need to run nodetool > repair ?
If Hinted Handoff works in your version of Cassandra, and that version is > 1.0, you "should" not need to repair if no node has crashed or been down for longer than max_hint_window_in_ms. This is because after 1.0, any failed write to a remote replica results in a hint, so any DELETE should eventually be fully replicated. However hinted handoff is meaningfully broken between 1.1.0 and 1.1.6 (unreleased) so you cannot rely on the above heuristic for consistency. In these versions, you have to repair (or read repair 100% of keys) once every GCGraceSeconds to prevent the possibility of zombie data. If it were possible to repair on a per-columnfamily basis, you could get a significant win by only repairing columnfamilies which take DELETE traffic. https://issues.apache.org/jira/browse/CASSANDRA-4772 =Rob -- =Robert Coli AIM>ALK - rc...@palominodb.com YAHOO - rcoli.palominob SKYPE - rcoli_palominodb
