Disk space is a critical resource for the HA Qpid broker.
In case when a Replica goes down (or falls behind the Master in 2 node cluster where the Master is designated primary) and the Master continues running, the non-replicated store files are kept on the Masters disk for the period of time as specified in je.rep.repStreamTimeout JE setting in order to replicate this data later when the Replica is back. This setting is set to 1 hour by default by the broker. The setting can be overridden as described in Section 12.5.1, “Passing BDB environment and replication configuration options”.
Depending from the application publishing/consuming rates and message sizes, the disk space might become overfull during this period of time due to preserved logs. Please, make sure to allocate enough space on your disk to avoid this from happening.