I am not sure what is happening but it has happened thrice. It is happening that merkle trees are not received from nodes of other data center. Getting issue on similar lines as mentioned here https://user.cassandra.apache.narkive.com/GTbqO6za/repair-hangs-when-merkle-tree-request-is-not-acknowledged
Regards Manish On Tue, Jan 18, 2022, 18:18 Bowen Song <bo...@bso.ng> wrote: > Keep reading the log on the initiator and the node sending the merkle > tree, anything follows that? FYI, not all log has the repair ID in it, > therefore please read the relevant logs in the chronological order without > filtering (e.g. "grep") on the repair ID. > > I'm sceptical network issue is causing all this. The merkle tree is send > over TCP connections, therefore some dropped packets over a few second of > network connectivity issue occasionally should not cause any issue to the > repair. You should only start to see network related issues if the network > problem persists over a period of time close to or longer than the timeout > values set in the cassandra.yaml file, in the case of repair it's the > request_timeout_in_ms which is default to 10 seconds. > > Carry on examine the logs, you may find something useful. > > BTW, talking about stuck repair, in my experience this can happen if two > or more repairs were ran concurrently on the same node (regardless which > node was the initiator) involving the same table. This could happen if you > accidentally ran "nodetool repair" on two nodes and both involve the same > table, or if you cancelled and then restarted a "nodetool repair" on a node > without waiting or killing the remannings of the first repair session on > other nodes. > On 18/01/2022 11:55, manish khandelwal wrote: > > In the system logs, on the node where repair was initiated, I see that the > node has requested merkle tree from all nodes including itself > > INFO [Repair#3:1] 2022-01-14 03:32:18,805 RepairJob.java:172 - *[repair > #6e3385e0-74d1-11ec-8e66-9f084ace9968*] Requesting merkle trees for > *tablename* (to [*/xyz.abc.def.14, /xyz.abc.def.13, /xyz.abc.def.12, > /xyz.mkn.pq.18, /xyz.mkn.pq.16, /xyz.mkn.pq.17*]) > INFO [AntiEntropyStage:1] 2022-01-14 03:32:18,841 RepairSession.java:180 > - [repair #6e3385e0-74d1-11ec-8e66-9f084ace9968] Received merkle tree for > *tablename* from */xyz.mkn.pq.17* > INFO [AntiEntropyStage:1] 2022-01-14 03:32:18,847 RepairSession.java:180 > - [repair #6e3385e0-74d1-11ec-8e66-9f084ace9968] Received merkle tree for > *tablename* from */xyz.mkn.pq.16* > INFO [AntiEntropyStage:1] 2022-01-14 03:32:18,851 RepairSession.java:180 > - [repair #6e3385e0-74d1-11ec-8e66-9f084ace9968] Received merkle tree for > *tablename* from */xyz.mkn.pq.18* > INFO [AntiEntropyStage:1] 2022-01-14 03:32:18,856 RepairSession.java:180 > - [repair #6e3385e0-74d1-11ec-8e66-9f084ace9968] Received merkle tree for > *tablename* from */xyz.abc.def.14* > Line 2480: INFO [AntiEntropyStage:1] *2022-01-14 03:32:18*,876 > RepairSession.java:180 - [*repair #6e3385e0-74d1-11ec-8e66-9f084ace9968*] > Received merkle tree for *tablename* from */xyz.abc.def.12* > > As per the logs merkle tree is not received from node with ip > *xyz.abc.def.13* > > In the system logs of node with ip *xyz.abc.def.13, *I can see following > logs > > NFO [AntiEntropyStage:1] *2022-01-14 03:32:18*,850 Validator.java:281 - > [*repair > #6e3385e0-74d1-11ec-8e66-9f084ace9968*] Sending completed merkle tree to > */* *xyz.mkn.pq.17* for *keyspace.tablename* > > From the above I inferred that the repair task has become orphaned since > it is waiting for merkle tree from a node and it is not going to receive it > since it has been lost in the network somewhere between. > > Regards > Manish > > On Tue, Jan 18, 2022 at 4:39 PM Bowen Song <bo...@bso.ng> wrote: > >> The entry in the debug.log is not specific to a repair session, and it >> could also be caused by reasons other than network connectivity issue, such >> as long STW GC pauses. I usually don't start troubleshooting an issue from >> the debug log, as it can be rather noisy. The system.log is a better >> starting point. >> >> If I was to troubleshoot the issue, I would start from the system logs on >> the node that initiated the repair, i.e. the node you ran the "nodetool >> repair" command on. Follow the repair ID (an UUID) in the logs on all nodes >> involved in the repair and read all related logs in chronological order to >> find out what exactly had happened. >> >> BTW, If the issue is easily reproducible, I would re-run the repair with >> a reduce scope (such as table and token range) to get less logs related to >> the repair session. Less logs means less time spend on reading and >> analysing them. >> >> Hope this helps. >> On 18/01/2022 10:03, manish khandelwal wrote: >> >> I have a Cassandra 3.11.2 cluster with two DCs. While running repair , I >> am observing the following behavior. >> >> I am seeing that node is not able to receive merkle tree from one or two >> nodes. Also I am able to see that the missing nodes did send the merkle >> tree but it was not received. This make repair hangs on consistent basis. >> In netstats I can see output as follows >> >> *Mode: NORMAL* >> *Not sending any streams. Attempted: 7858888* >> *Mismatch (Blocking): 2560* >> *Mismatch (Background): 17173* >> *Pool Name Active Pending Completed Dropped* >> *Large messages n/a 0 6313 3* >> *Small messages n/a 0 55978004 3* >> *Gossip messages n/a 0 93756 125**Does it represent network issues? In >> Debug logs I saw something*DEBUG >> [MessagingService-Outgoing-hostname/xxx.yy.zz.kk-Large] 2022-01-14 >> 05:00:19,031 OutboundTcpConnection.java:349 - Error writing to >> hostname/xxx.yy.zz.kk >> java.io.IOException: Connection timed out >> at sun.nio.ch.FileDispatcherImpl.write0(Native Method) ~[na:1.8.0_221] >> at sun.nio.ch.SocketDispatcher.write(SocketDispatcher.java:47) >> ~[na:1.8.0_221] >> at sun.nio.ch.IOUtil.writeFromNativeBuffer(IOUtil.java:93) >> ~[na:1.8.0_221] >> at sun.nio.ch.IOUtil.write(IOUtil.java:65) ~[na:1.8.0_221] >> at sun.nio.ch.SocketChannelImpl.write(SocketChannelImpl.java:471) >> ~[na:1.8.0_221] >> at java.nio.channels.Channels.writeFullyImpl(Channels.java:78) >> ~[na:1.8.0_221] >> at java.nio.channels.Channels.writeFully(Channels.java:98) ~[na:1.8.0_221] >> at java.nio.channels.Channels.access$000(Channels.java:61) ~[na:1.8.0_221] >> at java.nio.channels.Channels$1.write(Channels.java:174) ~[na:1.8.0_221] >> at >> net.jpountz.lz4.LZ4BlockOutputStream.flushBufferedData(LZ4BlockOutputStream.java:205) >> ~[lz4-1.3.0.jar:na] >> at >> net.jpountz.lz4.LZ4BlockOutputStream.write(LZ4BlockOutputStream.java:158) >> ~[lz4-1.3.0.jar:na] (edited) >> >> Does this show any network fluctuations? >> >> Regards >> Manish >> >> >>
