[syslog-ng] Disk based queuing with rsyslog?

Gergely Nagy algernon at balabit.com
Wed May 9 10:35:45 UTC 2018

>>>>> "Delon" == Delon Lee Di Lun <lee.delon2005 at gmail.com> writes:

    Delon> However, now. I see the documentation mention that flow control can be used
    Delon> in conjunction with disk based buffering. How does flow control plays a
    Delon> part?

The documentation has a chapter on flow-control, which explains the
purpose, and the behaviour of it:

    Delon> Flow control only works within the syslog-ng application? From the source
    Delon> to dest? Or it has the capability to detect the flow rate from the remote
    Delon> syslog-ng client and can "command" the syslog-ng client to slow down if the
    Delon> syslog-ng server cannot handle the load?

Yes, it only works within a single syslog-ng instance. But if you have
syslog-ng on both client and server, if flow-control kicks in on the
server, and it slows down accepting messages, then flow-control will
also kick in on the client (because it detects that messages are not
going out fast enough), and it will start buffering (to disk too, if so
configured). This way, you'll only lose messages if all queues fill up.


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