Check the logs for messages about nodes going up and down, and also look at the MessagingService MBean for timeouts. If the node in DR 2 times out replying to DR1 the DR1 node will store a hint.
Also when hints are stored they are TTL'd to the gc_grace_seconds for the CF (IIRC). If that's low the hints may not have been delivered. Am not aware of any specific tracking for failed hints other than log messages. A ----------------- Aaron Morton New Zealand @aaronmorton Co-Founder & Principal Consultant Apache Cassandra Consulting http://www.thelastpickle.com On 28/09/2013, at 12:01 AM, Oleg Dulin <oleg.du...@gmail.com> wrote: > Here is some more information. > > I am running full repair on one of the nodes and I am observing strange > behavior. > > Both DCs were up during the data load. But repair is reporting a lot of > out-of-sync data. Why would that be ? Is there a way for me to tell that WAN > may be dropping hinted handoff traffic ? > > Regards, > Oleg > > On 2013-09-27 10:35:34 +0000, Oleg Dulin said: > >> Wanted to add one more thing: >> I can also tell that the numbers are not consistent across DRs this way -- I >> have a column family with really wide rows (a couple million columns). >> DC1 reports higher column counts than DC2. DC2 only becomes consistent after >> I do the command a couple of times and trigger a read-repair. But why would >> nodetool repair logs show that everything is in sync ? >> Regards, >> Oleg >> On 2013-09-27 10:23:45 +0000, Oleg Dulin said: >>> Consider this output from nodetool ring: >>> Address DC Rack Status State Load >>> Effective-Ownership Token >>> 127605887595351923798765477786913079396 >>> dc1.5 DC1 RAC1 Up Normal 32.07 GB 50.00% >>> 0 >>> dc2.100 DC2 RAC1 Up Normal 8.21 GB 50.00% 100 >>> dc1.6 DC1 RAC1 Up Normal 32.82 GB 50.00% >>> 42535295865117307932921825928971026432 >>> dc2.101 DC2 RAC1 Up Normal 12.41 GB 50.00% >>> 42535295865117307932921825928971026532 >>> dc1.7 DC1 RAC1 Up Normal 28.37 GB 50.00% >>> 85070591730234615865843651857942052864 >>> dc2.102 DC2 RAC1 Up Normal 12.27 GB 50.00% >>> 85070591730234615865843651857942052964 >>> dc1.8 DC1 RAC1 Up Normal 27.34 GB 50.00% >>> 127605887595351923798765477786913079296 >>> dc2.103 DC2 RAC1 Up Normal 13.46 GB 50.00% >>> 127605887595351923798765477786913079396 >>> I concealed IPs and DC names for confidentiality. >>> All of the data loading was happening against DC1 at a pretty brisk rate, >>> of, say, 200K writes per minute. >>> Note how my tokens are offset by 100. Shouldn't that mean that load on each >>> node should be roughly identical ? In DC1 it is roughly around 30 G on each >>> node. In DC2 it is almost 1/3rd of the nearest DC1 node by token range. >>> To verify that the nodes are in sync, I ran nodetool -h localhost repair >>> MyKeySpace --partitioner-range on each node in DC2. Watching the logs, I >>> see that the repair went really quick and all column families are in sync! >>> I need help making sense of this. Is this because DC1 is not fully >>> compacted ? Is it because DC2 is not fully synced and I am not checking >>> correctly ? How can I tell that there is still replication going on in >>> progress (note, I started my load yesterday at 9:50am). > > > -- > Regards, > Oleg Dulin > http://www.olegdulin.com > >
