>>>>> "Mike" == Mike Long <mike.long@analog.com> writes:

    >> Today Bind has started to go strange on us. We're running Bind
    >> 4.9.4PL1 under NetBSD 1.1. When we 'kill -HUP' the named, it
    >> fails to reload the primary zones, saying 'Too many open
    >> files'. It also seems to be doing this sometimes for zone
    >> transfers. Does anybody have any idea why it does this (it
    >> surely can't be *really* running out of files, it only needs
    >> about 4 sockets and, err, no files)? Killing the named
    >> completely and restarting it doesn't help, rebooting the
    >> machine does.

Maybe your kernel is running out of file descriptors? BTW, the current
version of bind is 4.9.5P1.

    Mike> fstat(8) may be able to tell you which process(es) are
    Mike> hogging file descriptors.

lsof will do this much better and tell you lots more besides - like
how many sockets are being used, what files are mmapped, current
directories and so on.