We have an ELA build 8000. Index drive is 450 gb and it is mostly full. We don't have a lot of servers on it about 100 or so. And under F:\Archives\Indexes\2\univindexes\cold folder I see archives which is 6 month old, although our "
Retain Archive Logs" interval is setup to 1 month and "
Compress Index files older" than and "Compress Universal Index files older than" both setup to 3 days.