Unable to analyze core dump logs using cbanalyze-core tool

I am frequently seeing core.**** files getting generated at /opt/couchbase/var/lib/couchbase on one of the couchbase hosts. I am trying to use the cbanalyze-core tool but im unable to understand the argument to be passed after -r option.

Below is the syntax:
cbanalyze-core -r [root] -f [reportfile] [corefile]
-r [root]--------- Search for the binary in root.
Kindly help with what may be passed as an argument to -r option.