I built my house with a dedicated music room 25' X 23' with an 8' X 6' equipment alcove. Unfortunately, I kept buying records and CDs since 1993 when I moved in. I built in seismic reinforced shelving along most of three walls (worked great in the 1994 Northridge earthquake), I have 10 drawers from CAN-AM for CD storage and several racks on the walls for additional storage (overage). I also have about 2,500 LPs and 2,000 78s in a storage building I installed in 1998. So, yes, I have several 1000s too many records. I sold 18,000 records in the past. I have a rule for myself, if I don't potentially want to hear a recording three times annually, out it goes. Those 2,000 78s are for sale for $1,000. They weigh a ton.
As to knowing where my recordings are, over 75% are in alphabetical and/or label order by music type (rock, opera, vocalists, pop, jazz, instrumentalists, etc). Also, about 70% are listed alphabetically on computer files in order per music type. Now that I have so many business responsibilities, I have less time to edit my computer files. I just spend 1.5 hours nightly listening to music and whenever I can grab more time, such as on weekends.
Actually, I have friends who have warehouses filled with records. Tom Null (owner Varese Sarabande/Newport Classics) has over a million stored nearby, the late Rod Mckuen (who hired a staff for his huge collection), the late Music Man Murray and another late collector-seller in San Bernardino had over a million records each (their collections were purchased by the Brazillian collector who has at least 8 million records).
My friends who are mastering engineers Kevin Gray, Steve Hoffman and Robert Pincus should keep at least a carton of each of their remasterings in a warehouse. It would have made them rich if they did-note the prices of DCC LPs and CDs alone.