Hi @saito_lab The Universal Forwarder does not indefinitely buffer data in memory, you typically have the default maxQueueSize (See https://help.splunk.com/en/data-management/splunk-enterprise-admin-manual/9.2/configuration-file-reference/9.2.2-configuration-file-reference/outputs.conf#:~:text=false%0A%0A%23%2D%2D%2D%2DQueue%20Settings%2D%2D%2D%2D-,maxQueueSize%20%3D%20%5B,-%3Cinteger%3E%7C%3Cinteger%3E%5BKB ) which is relatively small and is held in memory, not written to disk, therefore setting this value too high can cause an OutOfMemory failure and this, or a restart, would lose the queued content. When the queue fills it will block the various pipelines leading to it and input will stop, if this is a monitor input stanza it will stop reading the files, if its a Splunk2Splunk input then it will stop accepting new data and the client sending the data will start queuing. If you have a Heavy Forwarder you could look at persistentQueueSize which stores queued data on disk instead of memory. Regarding Q3 - The UF will automatically reconnect and resume forwarding, for monitor:// inputs, it picks up from the last checkpoint in fishbucket and reads forward through any remaining file data. Q4 - Enable maintenance mode on the indexer cluster before performing restarts. Are you thinking of having all indexers down at one go or performing rolling restarts? 🌟 Did this answer help you? If so, please consider: Adding karma to show it was useful Marking it as the solution if it resolved your issue Commenting if you need any clarification Your feedback encourages the volunteers in this community to continue contributing.
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