service/max_snapshots is a SAP Parameter attribute which is used to control Maximum number of snapshots to be archived 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 .
Maximum number of snapshots that the start service is to archive for
each instance in the DIR_GLOBAL directory. If more snapshots are
generated, the oldest is deleted in each case.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.