Even if HH works fine, HH will not be created until the failure detector marks the node is dead. HH will not be created for partially timeouted mutation request ( but meets CL ) also... In my understanding...
On 2012/10/11, at 5:55, Rob Coli <rc...@palominodb.com> wrote: > 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
