sbin/devd/devd.cc
    Increase the size of devd's client socket's send buffer from the
    default (8k) to 128k.  This prevents clients from getting
    POLLHUPped during event storms.  For example, during zpool creation,
    the kernel emits a resource.fs.zfs.statechange event for every vdev
    in the pool.  A 128k buffer is large enough to hold the statechange
    events for a pool with nearly 800 drives.

sbin/devd/devd.cc
    Promoting the SIGINFO handler's log message from LOG_INFO to
    LOG_NOTICE, and promoting the "Processing event ..." message from
    LOG_DEBUG to LOG_INFO.  Setting the logfile to LOG_NOTICE with this
    change will have the same result as setting it to LOG_INFO without
    this change.  Setting it to LOG_INFO with this change will include
    the useful "Processing event ..." messages that were previously at
    LOG_DEBUG, without including useless messages like "Pushing table".

    The intent of this change is that one can log "Processing event ..."
    without logging "Pushing table" and related messages that are sent
    for every event.  The number of lines actually logged is reduced by
    about 75% by making this change and setting syslog to LOG_INFO vs
    setting syslog to LOG_DEBUG.

etc/syslog.conf
    Changing the recommended loglevel to notice instead of info.