Drop a 500 GB table, any consequences?
From MS:

When the DELETE statement is executed using a row lock, each row in the table is locked for deletion. TRUNCATE TABLE always locks the table (including a schema (SCH-M) lock) and page but not each row.

https://docs.microsoft.com/en-us/sql/t-sql/statements/truncate-table-transact-sql?redirectedfrom=MSDN&amp;view=sql-server-ver15

Where possible I'd run it in a dev environment first and run sp_whoisactive @get_locks=1. This will give you some reassurance over what's going to happen in terms of locking/blocking. Appreciate this may not be possible with a massive DB.

Regarding the mirror, TRUNCATE is still a logged operation so the table will also be truncated on the mirror. This may help https://www.sqlservercentral.com/forums/topic/truncate-table-on-mirrored-db