The disclosure supports both trickle and burst input/output (I/O) admission rates in journaling file systems. Examples include receiving incoming data; based at least on receiving the incoming data, generating metadata for a journal entry; adding the metadata to an active metadata batch; issuing a data write to write the incoming data to a storage medium; monitoring for a first trigger comprising determining that a data write for an entry in the active metadata batch is complete; based at least on the first trigger, closing the active metadata batch; and issuing a journal write to write entries of the active metadata batch to the storage medium. A second trigger comprises determining that a batch open time exceeds a selected percentage of a moving average of data write durations. A third trigger comprises determining that a batch counter exceeds a count threshold. These triggers work together to reduce I/O latencies.