I have a CatalogData folder for one our 7 Mailbox Databases that is growing at an alarming rate and I see that there are mailboxes that have items over a year old when 3mo's should be the oldest - retention policy purges all but tasks, notes, and calendar We caught it before the drive space filled. Yesterday It even caused our users to complain of outlook performance. I also noticed that the Copy Queue length is high for all of the DB's. This one DB with the Indexing issue no longer has a DB copy like the others - I suspended the Database copy and the deleted it taking a guess that because of the large growing Indexing files the "copy" was having trouble keeping up and causing the server to fall behind.
I also dismounted that DB, shut down the M$ Exchange Indexer service, deleted the Catalog files, then started the service, and then mounted he DB again. The files rebuilt all night and they are now up to about 17 GB - originally found it at 80+ GB. The DB is 230G in size. I'm having trouble finding what is causing this, that in itself may reveal the answer of how to fix this.
1 CAS & HUB server running Win 2012 srv
2 MBX DB servers running Win 2012 srv