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
<http://sun.nio.ch/>.FileDispatcherImpl.write0(Native Method)
~[na:1.8.0_221]
at sun.nio.ch
<http://sun.nio.ch/>.SocketDispatcher.write(SocketDispatcher.java:47)
~[na:1.8.0_221]
at sun.nio.ch
<http://sun.nio.ch/>.IOUtil.writeFromNativeBuffer(IOUtil.java:93)
~[na:1.8.0_221]
at sun.nio.ch <http://sun.nio.ch/>.IOUtil.write(IOUtil.java:65)
~[na:1.8.0_221]
at sun.nio.ch
<http://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
