On Postgres 9.5 I had a table that grew to 30GB, but it was ultimately mostly dead rows. After cleaning it up with a
vacuum full, postgres reports that the table size is now around 500MB. However, I see no space being released to the OS.
I found PostgreSQL - VACUUM FULL does not free space back to the OS which suggests the WAL files might be the culprit, but these are present on a different disk so it shouldn't affect my actual data disk at all.
I have confirmed that there are no other long running transactions or autovacuum's that might be locking the table.
What can I look at to figure out why my space isn't being released?