OK. So changing the checkpoint internal to 300 seconds might help reduce IO a bit. But it will cause the repo to become much larger, and it will take much longer to startup whenever you restart NiFi.
The variance in size between nodes is likely due to how recently it’s checkpointed. If it stays large like 31 GB while the other stay small, that would be interesting to know. Thanks -Mark On Mar 22, 2023, at 12:45 PM, Joe Obernberger <[email protected]> wrote: Thanks for this Mark. I'm not seeing any large attributes at the moment but will go through this and verify - but I did have one queue that was set to 100k instead of 10k. I set the nifi.cluster.node.connection.timeout to 30 seconds (up from 5) and the nifi.flowfile.repository.checkpoint.interval to 300 seconds (up from 20). While it's running the size of the flowfile repo varies (wildly?) on each of the nodes from 1.5G to over 30G. Disk IO is still very high, but it's running now and I can use the UI. Interestingly at this point the UI shows 677k files and 1.5G of flow. But disk usage on the flowfile repo is 31G, 3.7G, and 2.6G on the 3 nodes. I'd love to throw some SSDs at this problem. I can add more nifi nodes. -Joe On 3/22/2023 11:08 AM, Mark Payne wrote: Joe, The errors noted are indicating that NiFi cannot communicate with registry. Either the registry is offline, NiFi’s Registry Client is not configured properly, there’s a firewall in the way, etc. A FlowFile repo of 35 GB is rather huge. This would imply one of 3 things: - You have a huge number of FlowFiles (doesn’t seem to be the case) - FlowFiles have a huge number of attributes or - FlowFiles have 1 or more huge attribute values. Typically, FlowFile attribute should be kept minimal and should never contain chunks of contents from the FlowFile content. Often when we see this type of behavior it’s due to using something like ExtractText or EvaluateJsonPath to put large blocks of content into attributes. And in this case, setting Backpressure Threshold above 10,000 is even more concerning, as it means even greater disk I/O. Thanks -Mark On Mar 22, 2023, at 11:01 AM, Joe Obernberger <[email protected]><mailto:[email protected]> wrote: Thank you Mark. These are SATA drives - but there's no way for the flowfile repo to be on multiple spindles. It's not huge - maybe 35G per node. I do see a lot of messages like this in the log: 2023-03-22 10:52:13,960 ERROR [Timer-Driven Process Thread-62] o.a.nifi.groups.StandardProcessGroup Failed to synchronize StandardProcessGroup[identifier=861d3b27-aace-186d-bbb7-870c6fa65243,name=TIKA Handle Extract Metadata] with Flow Registry because could not retrieve version 1 of flow with identifier d64e72b5-16ea-4a87-af09-72c5bbcd82bf in bucket 736a8f4b-19be-4c01-b2c3-901d9538c5ef due to: Connection refused (Connection refused) 2023-03-22 10:52:13,960 ERROR [Timer-Driven Process Thread-62] o.a.nifi.groups.StandardProcessGroup Failed to synchronize StandardProcessGroup[identifier=bcc23c03-49ef-1e41-83cb-83f22630466d,name=WriteDB] with Flow Registry because could not retrieve version 2 of flow with identifier ff197063-af31-45df-9401-e9f8ba2e4b2b in bucket 736a8f4b-19be-4c01-b2c3-901d9538c5ef due to: Connection refused (Connection refused) 2023-03-22 10:52:13,960 ERROR [Timer-Driven Process Thread-62] o.a.nifi.groups.StandardProcessGroup Failed to synchronize StandardProcessGroup[identifier=bc913ff1-06b1-1b76-a548-7525a836560a,name=TIKA Handle Extract Metadata] with Flow Registry because could not retrieve version 1 of flow with identifier d64e72b5-16ea-4a87-af09-72c5bbcd82bf in bucket 736a8f4b-19be-4c01-b2c3-901d9538c5ef due to: Connection refused (Connection refused) 2023-03-22 10:52:13,960 ERROR [Timer-Driven Process Thread-62] o.a.nifi.groups.StandardProcessGroup Failed to synchronize StandardProcessGroup[identifier=920c3600-2954-1c8e-b121-6d7d3d393de6,name=Save Binary Data] with Flow Registry because could not retrieve version 1 of flow with identifier 7a8c82be-1707-4e7d-a5e7-bb3825e0a38f in bucket 736a8f4b-19be-4c01-b2c3-901d9538c5ef due to: Connection refused (Connection refused) A clue? -joe On 3/22/2023 10:49 AM, Mark Payne wrote: Joe, 1.8 million FlowFiles is not a concern. But when you say “Should I reduce the queue sizes?” it makes me wonder if they’re all in a single queue? Generally, you should leave the backpressure threshold at the default 10,000 FlowFile max. Increasing this can lead to huge amounts of swapping, which will drastically reduce performance and increase disk utilization very significantly. Also from the diagnostics, it looks like you’ve got a lot of CPU cores, but you’re not using much. And based on the amount of disk space available and the fact that you’re seeing 100% utilization, I’m wondering if you’re using spinning disks, rather than SSDs? I would highly recommend always running NiFi with ssd/nvme drives. Absent that, if you have multiple disk drives, you could also configure the content repository to span multiple disks, in order to spread that load. Thanks -Mark On Mar 22, 2023, at 10:41 AM, Joe Obernberger <[email protected]><mailto:[email protected]> wrote: Thank you. Was able to get in. Currently there are 1.8 million flow files and 3.2G. Is this too much for a 3 node cluster with mutliple spindles each (SATA drives)? Should I reduce the queue sizes? -Joe On 3/22/2023 10:23 AM, Phillip Lord wrote: Joe, If you need the UI to come back up, try setting the autoresume setting in nifi.properties to false and restart node(s). This will bring up every component/controllerService up stopped/disabled and may provide some breathing room for the UI to become available again. Phil On Mar 22, 2023 at 10:20 AM -0400, Joe Obernberger <[email protected]><mailto:[email protected]>, wrote: atop shows the disk as being all red with IO - 100% utilization. There are a lot of flowfiles currently trying to run through, but I can't monitor it because....UI wont' load. -Joe On 3/22/2023 10:16 AM, Mark Payne wrote: Joe, I’d recommend taking a look at garbage collection. It is far more likely the culprit than disk I/O. Thanks -Mark On Mar 22, 2023, at 10:12 AM, Joe Obernberger <[email protected]><mailto:[email protected]> wrote: I'm getting "java.net.SocketTimeoutException: timeout" from the user interface of NiFi when load is heavy. This is 1.18.0 running on a 3 node cluster. Disk IO is high and when that happens, I can't get into the UI to stop any of the processors. Any ideas? I have put the flowfile repository and content repository on different disks on the 3 nodes, but disk usage is still so high that I can't get in. Thank you! -Joe -- This email has been checked for viruses by AVG antivirus software. www.avg.com<http://www.avg.com/> [https://s-install.avcdn.net/ipm/preview/icons/icon-envelope-tick-green-avg-v1.png]<http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient> Virus-free.www.avg.com<http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient>
