update doc and set new default

CHANGELOG.md

@@ -19,7 +19,7 @@
     * `-ingest-storage.read-consistency`: configures the default read consistency.
     * `-ingest-storage.migration.distributor-send-to-ingesters-enabled`: enabled tee-ing writes to classic ingesters and Kafka, used during a live migration to the new ingest storage architecture.
     * `-ingester.partition-ring.*`: configures partitions ring backend.
-* [CHANGE] Distributor: Previously incoming OTLP requests were size-limited by using limit from `-distributor.max-recv-msg-size` option. We have added option `-distributor.max-otlp-request-size` for OTLP request, which defaults to 80 MiB. #8574 
+* [CHANGE] Distributor: Previously incoming OTLP requests were size-limited by using limit from `-distributor.max-recv-msg-size` option. We have added option `-distributor.max-otlp-request-size` for OTLP request, which defaults to 20 MiB. #8574 
 * [ENHANCEMENT] Compactor: Add `cortex_compactor_compaction_job_duration_seconds` and `cortex_compactor_compaction_job_blocks` histogram metrics to track duration of individual compaction jobs and number of blocks per job. #8371
 * [ENHANCEMENT] Rules: Added per namespace max rules per rule group limit. The maximum number of rules per rule groups for all namespaces continues to be configured by `-ruler.max-rules-per-rule-group`, but now, this can be superseded by the new `-ruler.max-rules-per-rule-group-by-namespace` option on a per namespace basis. This new limit can be overridden using the overrides mechanism to be applied per-tenant. #8378
 * [ENHANCEMENT] Rules: Added per namespace max rule groups per tenant limit. The maximum number of rule groups per rule tenant for all namespaces continues to be configured by `-ruler.max-rule-groups-per-tenant`, but now, this can be superseded by the new `-ruler.max-rule-groups-per-tenant-by-namespace` option on a per namespace basis. This new limit can be overridden using the overrides mechanism to be applied per-tenant. #8425

docs/sources/mimir/configure/configuration-parameters/index.md

@@ -849,7 +849,7 @@ ha_tracker:
 # (experimental) Maximum OTLP request size in bytes that the distributors
 # accept. Requests exceeding this limit are rejected.
 # CLI flag: -distributor.max-otlp-request-size
-[max_otlp_request_size: <int> | default = 83886080]
+[max_otlp_request_size: <int> | default = 20971520]
 
 # (experimental) Max size of the pooled buffers used for marshaling write
 # requests. If 0, no max size is enforced.

docs/sources/mimir/manage/mimir-runbooks/_index.md

@@ -2242,13 +2242,13 @@ This error occurs when a distributor rejects an Otel write request because its m
 
 How it **works**:
 
-- The distributor implements an upper limit on the message size of incoming OTel write requests after decompression regardless of the compression type. Refer to [OTLP collector compression details](https://github.com/open-telemetry/opentelemetry-collector/blob/main/config/configgrpc/README.md#client-configuration) for more information.
+- The distributor implements an upper limit on the message size of incoming OTel write requests after decompression regardless of the compression type. Refer to [OTLP collector compression details](https://github.com/open-telemetry/opentelemetry-collector/tree/main/config/confighttp) for more information.
 - Configure this limit in the `-distributor.max-otlp-request-size` setting.
 
 How to **fix** it:
 
-- Increase the allowed limit in the `-distributor.max-otlp-request-size` setting.
 - If you use the batch processor in the OTLP collector, decrease the maximum batch size in the `send_batch_max_size` setting. Refer to [Batch Collector](https://github.com/open-telemetry/opentelemetry-collector/blob/main/processor/batchprocessor/README.md) for details.
+- Increase the allowed limit in the `-distributor.max-otlp-request-size` setting.
 
 ### err-mimir-distributor-max-write-request-data-item-size
 

pkg/distributor/distributor.go

@@ -240,7 +240,7 @@ func (cfg *Config) RegisterFlags(f *flag.FlagSet, logger log.Logger) {
 	cfg.RetryConfig.RegisterFlags(f)
 
 	f.IntVar(&cfg.MaxRecvMsgSize, "distributor.max-recv-msg-size", 100<<20, "Max message size in bytes that the distributors will accept for incoming push requests to the remote write API. If exceeded, the request will be rejected.")
-	f.IntVar(&cfg.MaxOTLPRequestSize, maxOTLPRequestSizeFlag, 80<<20, "Maximum OTLP request size in bytes that the distributors accept. Requests exceeding this limit are rejected.")
+	f.IntVar(&cfg.MaxOTLPRequestSize, maxOTLPRequestSizeFlag, 20<<20, "Maximum OTLP request size in bytes that the distributors accept. Requests exceeding this limit are rejected.")
 	f.IntVar(&cfg.MaxRequestPoolBufferSize, "distributor.max-request-pool-buffer-size", 0, "Max size of the pooled buffers used for marshaling write requests. If 0, no max size is enforced.")
 	f.DurationVar(&cfg.RemoteTimeout, "distributor.remote-timeout", 2*time.Second, "Timeout for downstream ingesters.")
 	f.BoolVar(&cfg.WriteRequestsBufferPoolingEnabled, "distributor.write-requests-buffer-pooling-enabled", true, "Enable pooling of buffers used for marshaling write requests.")