Experience of DAQDB as a distributed key-value store for the ATLAS data acquisition system

The Phase-II upgrade of the ATLAS experiment requires a redesign of the DAQ system, which will need to sustain 5.2 TB/s of input data for a rate of 1 MHz and provide access to 3 TB/s of these data to an event filtering farm. A possible implementation of the storage system consists of having a large storage buffer capable of decoupling the data readout from the data selection subsystem. DAQDB is an open-source implementation of a distributed key-value store for high-bandwidth, generic data storage in event-driven systems. We present the experience with integrating the system in the ATLAS DAQ framework.