[syslog-ng] lost messages with follow_freq()?

[Joe Shaw]

Hi,

I'm trying to use the follow_freq() option to tail a growing log file,
but not all of the messages are making it from the source end to the
destination end.  However, according to the statistics, no messages
are dropped.  I am using syslog-ng 2.0.9.

The file on the source side looks like this:

    -rw-r--r--  1 jshaw ita 251M Aug 19 15:07 dump-file

and is growing rather rapidly.  (It is basically being created by
replaying another stored log file.)  At this same point on the
destination side, this is the corresponding file:

    -rw-r--r--  1 root root 30M Aug 19 15:07 syslog-messages

And doing a diff on those files does show large missing chunks from
this file.

The source's statistics say that nothing has been dropped:

    Aug 19 15:07:45 source-host syslog-ng[18574]: Log statistics;
       dropped='tcp(AF_INET(10.1.73.18:2000))=0',
       processed='center(queued)=303967',
       processed='center(received)=304017',
       processed='destination(d_file)=6',
       processed='destination(d_remote)=303961',
       processed='source(s_sys)=56',
       processed='source(s_internal)=6',
       processed='source(s_file)=303955'

And on the destination side:

    Aug 19 15:08:04 dest-host syslog-ng[21023]: Log statistics;
        processed='center(queued)=318524',
        processed='center(received)=318521',
        processed='destination(d_file)=318521',
        processed='destination(d_stats)=3',
        processed='source(s_tcp)=318518',
	processed='source(s_internal)=3'

The source syslog-ng.conf file looks like this:

    options {
        sync(0);
        time_reopen(10);
        log_fifo_size(1000);
        long_hostnames(off);
        use_dns(yes);
        dns_cache(yes);
        use_fqdn(no);
        keep_hostname(yes);
        use_time_recvd(no);
        log_msg_size(65536);
        stats_freq(180);
    };

    source s_internal {
        internal();
    };

    source s_sys {
        file ("/proc/kmsg" log_prefix("kernel: "));
        unix-stream ("/dev/log");
    };

    source s_file {
        file("/ita/dump-file" follow_freq(1) flags(no-parse));
    };

    # Local destination for statistics
    destination d_file { file("/ita/syslog-messages" perm(0644)); };

    # Remote destination
    destination d_remote { tcp("dest-host" port(2000)); };

    # Send stats locally
    log { source(s_internal); destination(d_file); };

    # Send everything remotely
    log { source(s_internal); source(s_file); destination(d_remote); };

(Yes, the s_sys source is unused.)

On the destination side:

    options {
        sync(0);
        time_reopen(10);
        log_fifo_size(1000);
        long_hostnames(off);
        use_dns(yes);
        dns_cache(yes);
        use_fqdn(no);
        keep_hostname(yes);
        use_time_recvd(no);
        log_msg_size(65536);
        stats_freq(180);
    };

    # Remote source
    source s_tcp {
        tcp(port(2000) log-fetch-limit(128) max-connections(1000));
    };

    # syslog-ng statistics
    source s_internal {
        internal();
    };

    destination d_file {
        file("/ita/syslog-messages" perm(0644) log_fifo_size(100));
    };

    destination d_stats {
        file("/ita/syslog-stats" perm(0644));
    };

    # Save stats separately
    log { source(s_internal); destination(d_stats); };

    # Take all remote data and save it locally
    log { source(s_tcp); source(s_internal); destination(d_file); };

Any ideas what might be going on, or how to analyze this further?

Thanks,
Joe