rdisp/max_mbuf_entries is a SAP Parameter attribute which is used to control Maximum number of server entries information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
The list of active servers and their attributes is managed by every ABAP
server in a local buffer. This parameter configures the size of this
buffer.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.