Standby function after fail-over

Dear All,

We are in the midst of setting up fail-over arrangements between a primary
and secondary.

In the primary we have set the "archive_command" to copy the WAL(s) to a
shared directory "archive_dir" accessible by both Primary and Secondary.

As the Secondary is meant to fail-over. The "restore_command" will recover
the WAL(s) from "archive_dir". Once it becomes the Primary, can it assume
the role of the initial Primary to copy the WAL(s) to "archive_dir". This
means the "archive_command" and "archive_mode" settings need to be as same
as the initial Primary. One thing to note here is that the "hot_standby" has
been to "on" in the Secondary to function as a read-only server. What is
expected to happen if the Secondary fails-over? Can it copy the WAL(s) to
"archive_dir" just as the Primary did? Or must be change the setting after
the fail-over and initiate a restart?

Thank you.

Regards,

Selvam