Don't do pr repairs when using incremental repair, you'll just end up with loads of anti-compactions.
On 12 October 2016 at 19:11, Harikrishnan Pillai <hpil...@walmartlabs.com> wrote: > In my experience dc local repair node by node with > Pr and par options is best .full repair increased sstables > A lot and take days to compact it back or another > Easy option for repair is use a spark job ,read all data with > Consistency all and increase read repair chance to > 100 % or use Netflix tickler > > Sent from my iPhone > > On Oct 12, 2016, at 11:44 AM, Anuj Wadehra <anujw_2...@yahoo.co.in> wrote: > > Hi Leena, > > First thing you should be concerned about is : Why the repair -pr > operation doesnt complete ? > Second comes the question : Which repair option is best? > > > One probable cause of stuck repairs is : if the firewall between DCs is > closing TCP connections and Cassandra is trying to use such connections, > repairs will hang. Please refer https://docs.datastax.com/en/ > cassandra/2.0/cassandra/troubleshooting/trblshootIdleFirewall.html . We > faced that. > > Also make sure you comply with basic bandwidth requirement between DCs. > Recommended is 1000 Mb/s (1 gigabit) or greater. > > Answers for specific questions: > 1.As per my understanding, all replicas will not participate in dc local > repairs and thus repair would be ineffective. You need to make sure that > all replicas of a data in all dcs are in sync. > > 2. Every DC is not a ring. All DCs together form a token ring. So, I think > yes you should run repair -pr on all nodes. > > 3. Yes. I dont have experience with incremental repairs. But you can run > repair -pr on all nodes of all DCs. > > Regarding Best approach of repair, you should see some repair > presentations of Cassandra Summit 2016. All are online now. > > I attended the summit and people using large clusters generally use sub > range repairs to repair their clusters. But such large deployments are on > older Cassandra versions and these deployments generally dont use vnodes. > So people know easily which nodes hold which token range. > > > > Thanks > Anuj > > ------------------------------ > *From: *Leena Ghatpande <lghatpa...@hotmail.com>; > *To: *user@cassandra.apache.org <user@cassandra.apache.org>; > *Subject: *Repair in Multi Datacenter - Should you use -dc Datacenter > repair or repair with -pr > *Sent: *Wed, Oct 12, 2016 2:15:51 PM > > Please advice. Cannot find any clear documentation on what is the best > strategy for repairing nodes on a regular basis with multiple datacenters > involved. > > > We are running cassandra 3.7 in multi datacenter with 4 nodes in each data > center. We are trying to run repairs every other night to keep the nodes in > good state.We currently run repair with -pr option , but the repair process > gets hung and does not complete gracefully. Dont see any errors in the logs > either. > > > What is the best way to perform repairs on multiple data centers on large > tables. > > 1. Can we run Datacenter repair using -dc option for each data center? Do > we need to run repair on each node in that case or will it repair all nodes > within the datacenter? > > 2. Is running repair with -pr across all nodes required , if we perform > the step 1 every night? > > 3. Is cross data center repair required and if so whats the best option? > > > Thanks > > > Leena > > > > -- Kurt Greaves k...@instaclustr.com www.instaclustr.com
