rsdb/reco_ping_cmd is a SAP Parameter attribute which is used to control Syntax of the ping command 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 .
In the parallel database environment it is checked whether the previous
database instance can still be accessed during the DB reconnect. To do
so, a ping is issued for the server of the previous database instance,
if the parameter above is defined. The ping checks whether the previous
database server can still be accessed. The default value of
rsdb/reco_ping_cmd depends on the platform.
For example: rsdb/reco_ping_cmd =/etc/ping hostname 64 2
In the R/3 kernel, "hostname" is replaced with the correct host name of
the previous database server.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.