If renewal patterns as follows:
renewal-patterns = /tmp/krb5cc_*;/other/path/krb5cc_*
Will there be any performance impact or other problem if the second path does not exist on the client?
There should be no performance difference when the second path of the renewal-patterns setting does not exist on the client. If the second path doesn't exist, then the stat on the directory will fail, and we would not spend any time.