mediaserver
mediaserver-backup
above are redundancy mechanism that CVP call server IVR service uses to fetch media.
if mediaserver is not available, it automatically appends mediaserver-backup and try to fetch file from there.(this is there for asr tts also,)
so this mechanism will work well for your most of the microapps, as they all use CVP call servers IVR service to create VXML page and serves gateway.
coming to audium script, it is loaded on VXML server so VXML server is responsible for creating VXML page and serving to VG and there is no such mechanism like this in VXML server,
you have to completely rely on load balancer like ACE to achieve redundancy.
i hope this answers your query correctly.
regards
chintan
~please rate if helpful