The database backend used by mem_io is redis. It is an open source in-memory data structure store. mem_io store data, as well as metadata in the database.

The metadata is currently limited to the number of channels, stored using the key <mem_io_id>:meta:nr_channels as a string.

The data is stored in redis lists, one per channel ID. To minimize the risk of data loss, mem_io_store typically performs multiple push operations. The keys for the data have the following format: <mem_io_id>:data:<channel_id>. Here, <channel_id> is a zero-padded string representing the number of the channel.