This example involves an Aterisk message log of about 26GB, but with any server it usually does not get deleted until the server is stopped/restarted:
asterisk 13729 root 6w REG 0,41 27277943090 59097971 (deleted) /var/log/asterisk/messages
So if you've deleted a bunch of large logs, make sure you restart the server for them to regain your space.
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