I am trying to understand my prefetch and serve-expired statistics. The relevant parts of my unbound.conf is as follows:
prefetch: yes serve-expired: yes serve-expired-ttl: 86400 total.num.queries=95364 total.num.queries_ip_ratelimited=0 total.num.cachehits=78438 total.num.cachemiss=16926 total.num.prefetch=54883 total.num.zero_ttl=61509 total.num.recursivereplies=16926 You will notice that prefetch + zero_ttl exceeds the total number of queries so they must overlap. My guess is that every zero_ttl hit triggers a prefetch. So every zero_ttl increment is a prefetch increment but not every prefetch increment is a zero_ttl increment (i.e. < 10% TTL but not zero). However, if this were true prefetch would always be bigger than zero_ttl. As this is not the case, some questions: - What type of query increments prefetch and zero_ttl? - Is that prefetch number correct? 57% prefetch looks awful high. - Could the prefetch and zero_ttl statistics be reversed? If all zero_ttl triggered a prefetch then 61509 - 54883 = 6626 (7%) for non-zero_ttl looks believable. Thanks.
