--log-async[=<lines>]
Enable asynchronous logging and optionally set the limit on the
number of lines
which will be queued by dnsmasq when writing to the syslog is slow.
Dnsmasq can log asynchronously: this
allows it to continue functioning without being blocked by syslog, and
allows syslog to use dnsmasq for DNS queries without risking deadlock.
If the queue of log-lines becomes full, dnsmasq will log the
overflow, and the number of messages lost. The default queue length is
5, a sane value would be 5-25, and a maximum limit of 100 is imposed.