Hi, I do find a connection for 7cde3c5c-016b-1000-0000-00004c82c4b2 There was no Nifi version upgrade and I did not edit either node's flow or copy any flow.xml.gzs. All the mentioned folders exist and all the file permissions are as expected. I did notice the error after seeing clustering issues with Nifi. Basically I restarted the cluster but noticed that only 1/2 nodes were connected while the other node was stuck in a Connecting state for 10 minutes. So I restarted both the instances again and then they formed a cluster properly (but that is also when I saw the Warnings from my initial post). The primary node did switch on the second restart too.
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I am running Nifi 1.9.2 on a two-node cluster and it seems that I am losing data occasionally when I restart Nifi. I am seeing multiple instances of the following error (each error is for a different swap file)
2021-03-25 19:29:46,426 WARN [main] o.a.n.controller.FileSystemSwapManager Encountered unknown Swap File ./flowfile_repository/swap/1616081663634-7cde3c5c-016b-1000-0000-00004c82c4b2-98e280b7-c8e5-44d5-a94d-804cbde11f91.local.swap; will ignore this Swap File. This file should be cleaned up manually
and when I check the output of Nifi, I am seeing less data than expected around the time of the restart.
It seems to me that Nifi is swapping files but is unable to update the WriteAheadLog before Nifi is stopped. So, when Nifi starts again, it is unable to get the swapped files because there is no record of them in the WriteAheadLog. Let me know if this conclusion is correct and if so, how I can prevent this issue from occurring in the future.
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