> there are some nasty edge cases when you mix incremental repair and full repair ( https://issues.apache.org/jira/browse/CASSANDRA-13153 )
mixing incremental and full repairs will just make that more likely to happen, but although unlikely it's still possible for a similar condition to happen even when using incremental repair alone and this is ultimately fixed by CASSANDRA-9143 on 4.0 so I'd probably stick to Blake's suggestions on #13153: > It seems like we should recommend that users who delete data: > 1. Stop using incremental repair (pre-4.0) > 2. Run a full repair after upgrading to 4.0 before using incremental repair again > We should also recommend that even if users don't delete data, they should take a look at the amount of streaming their incremental repair is doing, and decide if it might be less expensive to just do full repairs instead. 2017-03-13 1:15 GMT-03:00 Jeff Jirsa <jji...@apache.org>: > > > On 2017-03-12 10:44 (-0700), Anuj Wadehra <anujw_2...@yahoo.co.in> wrote: > > Hi, > > > > Our setup is as follows: > > 2 DCS with N nodes, RF=DC1:3,DC2:3, Hinted Handoff=3 hours, Incremental > Repair scheduled once on every node (ALL DCs) within the gc grace period. > > > > I have following queries regarding incremental repairs: > > > > 1. When a node is down for X hours (where x > hinted handoff hours and > less than gc grace time), I think incremental repair is sufficient rather > than doing the full repair. Is the understanding correct ? > > > > Incremental repair SHOULD provide the same guarantees as regular repair. > > > 2. DataStax recommends "Run incremental repair daily, run full repairs > weekly to monthly". Does that mean that I have to run full repairs every > week to month EVEN IF I do daily incremental repairs? If yes, whats the > reasoning of running full repair when inc repair is already run? > > > > Reference: https://docs.datastax.com/en/cassandra/3.0/cassandra/ > operations/opsRepairNodesWhen.html > > > > I don't know why datastax suggests this, there are some nasty edge cases > when you mix incremental repair and full repair ( > https://issues.apache.org/jira/browse/CASSANDRA-13153 ) > > > 3. We run inc repair at least once in gc grace instead of the general > recommendation that inc repair should be run daily. Do you see any problem > with the approach? > > > > > > The more often you run it, the less data will be transferred, and the less > painful it will be. By running it weekly, you're making each run do 7x as > much as work compared to running it daily, increasing the chance of having > it impact your typical latencies. > > >
